

There’s no shortage of inspiration when it comes to using classic fall flavors in my baking. I love cinnamon spiced apples, anything pumpkin-filled and I’ve been dreaming of what to do with a fat butternut squash that’s been sitting on my kitchen counter for a good two weeks now. But after sampling some unique chocolates, I was inspired to make something a little less traditional this week.
Black truffles are most commonly used in savory dishes, but chocolatiers (such as the handsomely bearded Mast Brothers) have been incorporating them into chocolate. After sampling some, I was instantly smitten. Black truffles have a deep, earthy flavor that, to me, evokes feelings of the fall season. Depending on the variety, they’ve been described as “reminiscent of undergrowth, wet earth … or dried fruit with a hint of cocoa“. The trouble is, truffles are expensive, but luckily there are less expensive ways to incorporate them into your confectionery.

First of all, the cake is topped with Urbani’s black truffle bonbons (I bought mine here). They’re small, dense little candies filled with black truffle pieces, nuts and chocolate. They’re rich and earthy, and after tasting one I knew they were destined to adorn a chocolate cake filled with pistachio cream.
Secondly, the chocolate frosting is infused with a small amount of black truffle oil. Now, as far as I know, da Rosario is the only brand of truffle oil that is 100% organic and natural. Most other truffle oils contain no real truffles and instead are made with synthetic flavoring. That said, only a very small amount of truffle oil is used in the frosting, so purchase what your budget will allow. In general, real is always better than fake, but I view using the oil in the same way I view using artificial candy flavorings. It’s okay to use in small quantities, and when options are limited.

The pistachio filling is one of my favorite elements of this cake. It’s hugely rich with pistachio flavor, and that’s thanks to 11 ounces of pure pistachio paste. I couldn’t find it locally, so I ordered it online. You can find it here or in bulk here. It’s truly worth seeking out!

I really love the way this cake turned out. In fact, I told my husband I might enter it in the Tennessee State Fair next year. The black truffle flavors mixed with pistachio makes me think it’d be right at home at a fine Italian restaurant. Yesterday I had a slice with strong coffee, and let me tell you, I’m having trouble imagining anything better!
If you’re new to the flavor of black truffles, I suggest you familiarize yourself with it before embarking upon this cake. It’s an acquired taste for some people. Kitchen specialty shops often have oil tasting stations, which is a good way to explore their savory notes as the oils are usually served with garlicky seasonings and baguette rounds. To get an idea of how the flavor will taste in chocolate frosting, seek out a small chocolate bar or bonbons with black truffle shavings incorporated.

Black Truffle-Pistachio Chocolate Cake
Ingredients
Dark chocolate cake
- 8 ounces dark chocolate chopped
- 1/2 cup/113 g butter softened
- 2 cups/440 g light brown sugar firmly packed
- 3 eggs
- 1 teaspoon vanilla extract
- 2 cups/310 g all-purpose flour
- 1/4 cup/30 g dark cocoa powder
- 2 teaspoons baking soda
- 1/2 teaspoon sea salt
- 1/2 cup/121 g buttermilk
- 1 cup/235 ml piping hot water
Pistachio filling
- 1/4 cup/32g all-purpose flour
- 1 teaspoon fine grain sea salt
- 2 cups/460g buttermilk or whole milk
- 2 cups/1 pound unsalted butter softened
- 1 cup/200g granulated sugar
- 1 can 11 ounces pistachio nut paste
Black Truffle Chocolate Frosting
- 8 ounces semisweet chocolate chopped
- 1 1/2 cups heavy whipping cream
- 1/4 teaspoon black truffle oil add more to taste, but be careful – it’s strong stuff!
- 12 black truffle bonbons such as Urbani or black truffle chocolate squares (such as Mast Brothers)
- 4 ounces ground pistachios
Instructions
Dark chocolate cake
- Preheat oven to 350°F.
- Grease three 9-inch cake pans and line the bottoms with circles of parchment paper.
- Melt chocolate in a small saucepan over low heat, or melt in the microwave in a microwave-safe bowl at 30 second intervals. Set aside.
- Beat the butter with an electric mixer until creamy. Add sugar and beat until combined. Add eggs one at a time, beating each until just incorporated. Stir in melted chocolate and vanilla.
- Sift together the flour, cocoa powder, baking soda and sea salt; add to the butter mixture alternately with the buttermilk, beginning and ending with the flour mixture. With the mixer running, gradually add in the hot water. Mix until the batter in consistent (batter will be thin).
- Pour batter into prepared pans and bake for 30 minutes, or until a toothpick tester comes out clean. Cool in the pans on wire racks 10 minutes; remove cakes from the pans and cool completely on wire racks.
Pistachio filling
- In a medium saucepan, whisk together flour and 1/2 cup of the milk until smooth. Set over medium heat and let cook for 3 minutes, or until slightly hot. Whisk in remaining milk and salt. Whisk constantly until the mixture is thickened (almost like pudding). Remove from heat and pour into a separate bowl. Place in the refrigerator until completely chilled. When cool, mixture will be thick like set custard.
- In a large bowl (or bowl of a stand mixer, if you have one) beat the butter and sugar together until fluffy. Beat in chilled flour mixture one tablespoon at a time on medium-high speed. When all the flour mixture is added beat on high speed until light and fluffy, about 6 minutes. Rub a little frosting between your fingers, if sugar granules remain, beat for 4 more minutes, or until granules cannot be detected with fingers. Beat in the pistachio paste a little at a time until well incorporated.
- Place a chocolate cake layer on a cake stand or serving plate and top with three cups of pistachio filling. Top with another cake layer and spread the remaining 3 cups of filling over the second layer. Top with the third and final layer. Refrigerate the filled cake while you make the frosting.
Black Truffle Chocolate Frosting
- Combine the chocolate and whipping cream in a saucepan. Cook over medium heat, whisking occasionally. When the mixture is steaming and the chocolate is melted remove from the heat. Add the truffle oil (add more to taste, but be careful – it’s strong stuff!). Whisk the mixture until the chocolate is completely melted and incorporated into the cream. Pour into a shallow dish and chill until the mixture reaches a pudding-like consistency, about 1 hour.
- Beat the mixture with an electric mixer until it is thick and spreadable. Transfer 2/3 cup of frosting to a piping bag fitted with a large star tip. Frost the cake evenly with the remaining icing and pipe rosettes around the top edge of the cake. Top every other piped rosette with a black truffle bonbon. Sprinkle the top with ground pistachios. Place the cake on a large baking sheet and toss ground pistachios along the bottom edge of the cake, allowing the excess to fall back into the pan.
- Store the cake in the refrigerator. Serve chilled or let slices come to room temperature before serving – it’s good both ways!
This is just too pretty! I would admire it the entire time I devoured it 😉
Dear Heather, That cake is simply beautiful!! I am sure it is as delicious as it looks. Catherine
What a stunner. It is definitely a prize-winning kind of cake with its looks and the creative flavors!
chocolate + pistachio = a match made in dessert heaven. and BLACK TRUFFLES?! over the top, that is amazing.
this cake is so elegant and beautiful – I love it!!
Incredible! With some gold glitter this may have to be added to my christmas bake list. It's getting quite long though ahh!
Jenna || Jennafifi.co.uk
Oh. My. Gosh. That is literally the prettiest most perfect cake I've ever seen! The flavor combo sounds to die for 🙂
Gorgeous cake and I love the setting too!
That is absolutely beautiful! I've never tried black truffle but after your recommendation I will have to sample it someday. Perhaps in chocolate 🙂
Oh Heather, this is some of your best work. Sincerely, this is beyond restaurant quality. Now I need to save some pennies so I can try this amazing and sophisticated combination of very decadent ingredients! Oh what I would give for just a bite of this!!!!
This cake is beautiful! It looks really delicious and it's also very pretty!
Absolutely beautiful! Some of my favorited flavors all in one stunning dessert!
Oh I would die for a slice of this cake! It looks just perfect!
This cake looks so delicious, love the addition of pistachio. Pinned!!
Looks amazing. I absolutely adore truffles (popcorn with truffle salt, anyone?) so I can only imagine how great this tastes
Wow this cake is a true masterpiece! I bet it tastes amaaazing!
This looks beyond great! Absolutely making it for the holidays!
Absolutely amazing looking cake! Going to try make this for xmas!~
-Miss Sennnaa
BLOG: http://miss-sennnaa.blogspot.com
I think I just died a little and went to heaven looking at this cake! So gorgeous and it sounds absolutely delicious!
great job…
The conversion to grams for butter is a bit weird, 1/2cup = 216g seems too much. The cake looks amazing though! gonna try it 🙂
Hi Wendy, that's a typo! Thank you for bringing it to my attention!
I love how the filling is hugely pistachio-flavored! Chocolate and pistachio is one of my favorite flavor combinations and the addition of black truffles is completely decadent!
is it normal that the pistachio filling is really liquid?
I made this cake for my best friend's birthday. It went over so well, another friend commissioned one for her husband's birthday. He said it was the best chocolate cake he'd ever had…I have to agree! Although, you could really put truffle oil on cardboard and I would probably eat it!
Delicious cake!!!
Delicious cake!!!