Zodiac Constellation Cake

This cake holds a colorful surprise inside! Galaxy blue, green, and purple hues are swirled in tangy buttermilk cake batter. The cake is wrapped in a night sky of black fondant with zodiac constellations painted on using white food color.

The Autumnal Equinox is on the horizon and if you're a fellow sky gazer, then you may have noticed signs of the season's change. Here in my corner of the world (Northern Hemisphere), daytime brings a shade of brilliant blue that is only visible in fall. Indoors the shadows move across the windowsills differently. Crisp nights make it easy to examine a new (old) set of constellations that have moved across the sky and have different orientation.

The whole thing makes me wax philosophical. I suppose looking at the night sky will do that. It made me consider the zodiac, which I've never put much stock into, but have on occasion nodded my head when someone explains the behavior of a Scorpio or Cancer. Each sign supposedly describes characteristics of each and every human being on earth. I've decided it's not such a stretch. My baker's brain chalked it up to this: We're all different slices from the same cake - why not? Sound overly poetic? Yet another side effect of star-gazing. As is this cake.

I'll begin at the beginning, which is a cake batter I refer to as 'Galaxy Swirl'. What does a galaxy taste like? It's tangy. I used my favorite vanilla-white cake recipe (it tints well with food color) and added a big dose of buttermilk. It makes for a beautiful cake crumb that slices like a dream.

The exterior of this cake is made with a great product made by Wilton: Decorator Preferred Fondant. If you're a fondant novice, then start with this stuff. Seriously. As long as humidity isn't high, you can roll it out without dusting or greasing your work surface. If you've ever tried to tint white fondant black with food color, then you know what hassle it is (I only ever achieve dark gray). I recommend buying ready-made black fondant because it will make this project easier and much more enjoyable.

If you're new to covering cakes with rolled fondant, you should certainly read this tutorial. My cake is a 7-inch round triple layer cake covered in vanilla buttercream and black fondant. This is our primed canvas, so to speak. It seems I'm always making a case for the 7-inch cake - yes, you'll need these pans or at the very least, this 7-inch pastry ring to trim 9-inch cakes to size - but smaller cakes are much easier to cover with fondant than larger cakes. I recommend starting small, especially if you are a beginner.

Painting this cake was so much fun! You'll need a small fine-tipped artists' brush. My old art professor would say "use the brush for painting the reflection of light in a grasshopper's eyeball". That is to say, a size zero or one round-tipped brush. You'll also need paint, and that comes in the form of bright white gel food color.  I used a small plate turned upside-down to lightly score a circle into the top of the cake, and then a straight edge to make a line through the middle. The circle is the earth's pattern around the sun and the line points to your choice of constellation or between two. I visited NASA's website and Universe Today to get pictures of constellations and zodiac symbols. You can find the top cake illustration here and this illustration was helpful for painting constellations on the sides of cake. The symbols and lines I used aren't too difficult to free-hand with a paint brush. For the constellations, I literally played connect the dots; drew 'stars' and connected them.

You'll also need a large-ish stiff bristle brush. Any large hog bristle brush will work (and no, I don't like the description hog bristle any more than you do). Dip the brush into the white food color, and then pull back the bristles with a finger and flick the paint onto the cake holding the brush about 4-inches from the cake's surface, until the cake is speckled with white 'stars'.

Cutting this cake is a real show-stopper! I love that each slice is unique, both inside and out. The brilliant swirly cake colors are attributed to a combination of Betty Crocker's gel food colors in bold, neon and classic. You can find them at the links provided, but you're likely to find them priced more affordably at your local grocery store.

The paper chalkboard picks are from Target, but I bought them so long ago I'm not sure they're still available. You can find similar picks here and here. I used the white food color to paint the zodiac names, and then placed the picks on their corresponding symbol.

I think this cake would be great for any solstice party (outdoors under the stars, weather permitting) and for - what else? - birthdays!

Zodiac Constellation Cake
Yields about 12 servings

Galaxy swirl cake batter
3 1/2 cups cake flour
1 Tbsp. plus 1 tsp baking powder
1/2 tsp salt
6 large egg whites, room temp
1 1/2 cups buttermilk, room temp
1 cup vegetable oil
1 1/2 cups sugar
2 tsp vanilla extract
Betty Crocker Bold: dark blue food color
Betty Crocker Classic: blue and green food colors
Betty Crocker Neon: neon purple food color

Frosting, fondant and décor supplies
1 recipe American buttercream (link)
24 ounces black ready-made fondant (I recommend Decorator Preferred)
Fondant smoother, such as Easy-Glide Smoother by Wilton
Americolor Bright White gel food color
Fine-tipped artists brush, round size 0 or 1
Large stiff bristle brush, round size 4 or larger
Black paper chalkboard picks, if using

Make the cakes: Preheat oven to 350 degrees. Grease three 7-inch cake pans (or two 9-inch cake pans) and line the bottoms with parchment circles. Sift together flour, baking powder, and salt; set aside. Whisk together egg whites, buttermilk, oil, sugar and vanilla in a separate bowl; set aside.
Add dry ingredients to wet ingredients in three additions; beat until smooth on medium-low speed after each addition.
Divide batter between three bowls. Tint one bowl with neon purple food color and mix until a vivid color is achieved. In a second bowl add equal additions of classic blue and green gel food color; mix until a vivid turquoise color is achieved. In a third bowl tint the batter with bold dark blue food color; mix until well combined. Place large spoonsful of each color batter in the pans, alternating them often so that the colors are well varied. Use a skewer to swirl and marble the batter. Bake the cakes 350 for 25 to 30 minutes, or until a toothpick tester inserted in the centers come out clean. Let cool slightly in pan, then turn out to cool completely. Level each cake with a serrated knife or cake leveler.

Frost the cake: Fill two cake layers each with 1/2 cup frosting. Stack the cakes, ending with the plain layer on top. Frost the entire cake with a thin layer of frosting (crumb coat) and refrigerate until firm, about 30 minutes. Cover the cake with another thicker layer of frosting making it as even as possible (find my tips here in this video) and chill the cake again until the frosting is solid, about 30 minutes.

Fondant work: Before rolling out fondant, knead it until it is a workable consistency. If fondant is sticky, knead in a little confectioners' sugar. Roll the fondant out into a large circle with a large rolling pin to about 1/8-inch thickness (you can also roll to 1/4 inch, thicker fondant is less likely to tear, but will create rounded edges on your cake). To keep fondant from sticking, lift and move as you roll. Add more confectioners' sugar if needed. Gently lift fondant over a rolling pin; position on cake. Shape fondant to sides of cake with Easy-Glide Smoother. I recommend using the Smoother because the pressure of your hands may leave impressions on the fondant. Beginning in the middle of the cake top, move the Smoother outward and down the sides to smooth and shape fondant to the cake and remove air bubbles. If an air bubble appears, insert a pin on an angle, release air and smooth the area again. Use the straight edge of the Smoother to mark fondant at the base of cake. Trim off excess fondant using a spatula or sharp knife. Your cake is now ready to decorate.

Paint the cake: Use the zodiac symbols and constellations templates linked in the blog post as a guide for painting the cake. Score a circle on top of the cake with a fondant tool or the dull edge of a butter knife, so that it’s within 1 1/2 inches of the cake’s edge. Use a piece of paper with a straight edge to score a line through the center of the circle. Using the fine-tipped paint brush and undiluted bright white gel food color, paint a perforated line in the scored circle. Paint a perforated line on the straight edge line, and then paint an arrow at one end and two arrow marks anywhere inside the circle. At the other end of the straight edge line, paint a circle (earth). Paint zodiac symbols around the top edge of the cake, outside the perforated circle. Have a small cup of water and paper towels to clean your paint brush when needed. If you make a mistake, use a little of the water on a paper towel to ‘erase’ the white food color (I ended up removing an entire constellation on the side of the cake and re-painting it!). Paint constellations corresponding to the symbols on top of the cake on the sides of the cake. I painted dots for ‘stars’ and then connected them. Take your time and paint the connecting lines as thin as possible. They’ll look best this way. Now, the messy bit: Dip the hog-bristle brush into undiluted white gel food color and pull the bristles back with your fingers. Flick the paint onto the cake holding the brush about 4-inches from the cake's surface, repeating the process until the cake is speckled all over with white 'stars'.

Allow the cake to air dry for 45 minutes before serving. If using the chalkboard picks, use white food color to paint zodiac names on them, and place the pics on top of the cake and on their corresponding symbols.

Cover lightly in plastic wrap and store at room temperature for up to 3 days.

link Zodiac Constellation Cake By Published: Zodiac Constellation Cake Recipe


  1. This cake is in everyone's stars. Such a thing of beauty!

  2. That is so cool. I love it inside and out. Thanks for sharing how you added the stars. That is a great technique and I will definitely give it a try.

  3. OMG! amazing cake, this going to be my week-end dessert

  4. Magnificent cake! I've always loved your work :)
    But I'd love to have it more glittery like the real sky. Just an afterthought, you could have speckled the cake with disco dust to get the glittery effect. (you can do this by brushing the cake with a wet brush followed by sprinkling edible disco dust on top. the lines and signs will have to wait to be painted once the cake dries I suppose)

    1. Thank you Roshini!

      I agree, sparkles would be so nice on this cake. I am hesitant to use disco dust because certain family members will not eat glitter! But they have no problem with black fondant... haha!


  5. Wow, this cake is amazing. I like the contrast of the colors and the black.

  6. I've just discovered your blog, and wow, what amazing bakes you make! This one is stunning.

  7. Such a gorgeous cake! It looks like a work of art. The fondant almost looks like a chalkboard! :)

  8. Super cool cake! I second the notion of buying ready-made black fondant! Although if you are up for a little chocolate on your cake, Satin Ice brand chocolate fondant can be made black with black gel coloring pretty easily and tastes scrumptious.

  9. I love all things glittery but Roshini's post recommending disco dust has me a bit worried. While disco dust is non-toxic, it is not considered edible. What I mean by that is that the product is not meant to be eaten. The disco dusted fondant should be removed and not consumed.

    1. Opinons are sure to vary on Disco Dust, but these days I tend to avoid using it. I have consumed sweets that have been disco dusted (and lived to tell the tale) but it's not at all appetizing. Very pretty effect, though! I appreciate this comment. Thank you!

  10. This is just amazing, I would have loved this on my birthday as a child! I think I'd still love it now!

  11. Where did you get the sparkly cake server? It's fabulous!

    1. Hi! I found it at Leif Shop, though it appears to be out of stock.


      They have a few solid colors in stock (link following). I have the carnation pink one, too, and it is gorgeous!


      If your heart is set on the silver glitter one (and who can blame you) the brand name is Sabre. I'd say a Google search will lead you to it!

  12. This is so beautiful! You're amazing~

  13. Wow the inside looks like the aurora borealis, perfect for a sky and stars themed cake! X

  14. Merhabalar, çok leziz ve iştah açıcı bir görüntüsü var. Ellerinize sağlık.


  15. Wow! This cake is so pretty! Pinning!

  16. Oh. My. God. I think I've found my next birthday cake! So incredible! Liv x

  17. Wow! That's amazing, you did an excellent job. I love the swirling colors. Now I want a piece! Hah.

  18. Good crap, this cake is gorgeous. I've never been a fan of the fondant covered cake (either making or or eating it), but I think this one might just make it worth going for. Thank you for this gorgeous idea!

  19. This is gorgeous! I love how the inside pops with color!

  20. This evening I finally had a chance to sit down and REALLY take a good look at this cake. I just absolutely love it. My niece and my sister-in-law have birthdays within just a couple of days of each other coming up in about 10 days and we always celebrate both birthdays at the same time. We have this very odd thing in my family, I have NO CLUE how this happened, but every single person's birthday is either very close to someone else's birthday as in these two or like my dad and brother, just two days apart or, on a holiday or other major event as for example I was born on my parent's first wedding anniversary, my mother was born on Mother's Day, my nephew Memorial Day weekend. We NEVER seem to be able to just celebrate one person's birthday. Well guess what that means for me, the "baker" in the family? Of course, I never have just one cake or dessert, I always have at least two. It was bad enough when I just did regular baking but when I took up cake decorating most of them want some sort of decorated cake. This cake is THE perfect answer for my niece. She likes every thing black and likes things different. She is definitely not the "girly girl" type who wants pink, pearls and bows, either as a child or now as an adult. I only have one disagreement with you in the cake though and that's your use of decorator's frosting by Wilton. I decided to use it for this same niece's college graduation cake this summer and it was a NIGHTMARE. I stopped using Wilton fondant years ago, it taste like I imagine wallpaper paste would taste like, its disgusting and no one in my family ever wants to eat it again. However, circumstances dictated that I needed premade fondant in a hurry. I reluctantly decided to give this new decorator's fondant a try. I managed to pull the cake together, but no help from this fondant. And serving the cake was even worse. It had turned sticky, nasty, and just awful. I'll never touch Wilton Fondant again. Thankfully there are other companies out there that make it. When making a cake as nice as the ones you create and share with the rest of us, I say go for the best right away and the best is NOT a Wilton fondant regardless of whatever advertising they do for it. I do want to say thank you to you for sharing your ideas and your hard work with the rest of us not as talented or creative as you. So many places and sites are now charging for tutorials and information, INCLUDING Wilton. I used to watch their "Bake, Decorate, Celebrate" show in PBS faithfully every morning. But, they had to jump on board the money bandwagon and do away with their "yearbook" which was the ONLY tool available for those without computer access and even on the computer, they're charging for more and more classes. Soon, Wilton will become just like America's Test Kitchen, which also used to be free to everyone and now is one of the greediest food sites on the Internet. This is why your free tutorials are so greatly appreciated by those of us who can't afford to pay for every idea we see.

  21. OMG! I absolutely love this cake! It's beautiful! The constellations are so cool! I want this for my birthday next year! I am one of the owners of Yumgoggle.com. I would love it if you would submit this cake. But even if you don't, I still love this cake!

  22. I've seen this post reblogged so many times on tumblr recently, I had no idea it came from here. Awesome job on the cake.

  23. This is so beautiful!

  24. This is honestly the prettiest cake I have ever seen. Can I order it from you? There is no way I can replicate that.


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