The pumpkin sponge cake portion will need to be made twice to yield the two 15x10 sheets needed for all 20 cakes. If you require less servings, the cake recipe can be made once and both filling recipes halved.
Preheat oven to 375° F. Grease 15 x 10-inch jelly-roll pan; line with parchment paper, or spray with flour-based baking spray. Cover a large work surface with parchment paper and lightly dust with powdered sugar.
Combine flour, baking powder, baking soda, cinnamon and salt in small bowl. Beat eggs and granulated sugar in the bowl of an electric mixer until thick and pale. Beat in pumpkin. Stir in flour mixture. Spread evenly into prepared pan.
Bake for 12 to 14 minutes or until top of cake springs back when touched. (If using a dark-colored pan, begin checking for doneness at 11 minutes.) Immediately loosen and turn cake onto the prepared parchment paper. Remove parchment paper that lined the pan from the cake, if necessary.
Bake the sponge recipe twice so that you have two 15x10 sheets of pumpkin sponge.
Cranberry filling
Place the cranberry sauce in a medium saucepan over medium heat. Add the sugar and stir until the mixture begins to steam. Stir in the orange zest. Using an immersion blender, blend the mixture right in the saucepan to a smooth puree. (If you don’t have an immersion blender, cool mixture and transfer to a blender pitcher to puree. Then return it to the saucepan and re-heat.)
In a small bowl, stir together the water and cornstarch to make a slurry. Add the mixture to the hot cranberry puree while whisking, and stir until thickened, 3-5 minutes. Remove from the heat an let cool. Add the orange liqueur and refrigerate until completely cool.
Cream cheese filling
Beat cream cheese, powdered sugar, butter, and vanilla extract in small mixer bowl until smooth.
Scrape down the bowl and mix again until light and fluffy
Assembly
Cut one of the pumpkin sponge cakes into thirds that you have three 10x5-inch long pieces. Spread one of the cake layers evenly with the cranberry filling. Top with a second sponge. Spread a layer of cream cheese filling on top of the second sponge evenly. Top with the third layer of sponge. Refrigerate the cake until firm, about 25 minutes.
Meanwhile, roll out half of the marzipan to slightly less than 1/4-inch thickness. Remove the cake from the refrigerator and brush the top with water (I used a kitchen-dedicated spray bottle to mist it). Place the marzipan on top of the cake and trim away the excess so that the marzipan fits the top of the cake exactly. Save marzipan scraps. Refrigerate again for 15 minutes.
Repeat the entire process of filling, covering, and chilling the second pumpkin sponge.
Remove the cakes from the refrigerator and score the marzipan down the center length of the cake using a serrated knife. Score width-wise every two inches so that you have 10 mini cakes portioned. Using gently sawing motions, cut the cakes at their score marks. Repeat the process with the second assembled cake so that you have 20 mini cakes.
In a small bowl, stir together the powdered sugar, 3 tablespoons milk or cream, and vanilla extract. Whisk until thick glaze forms. Add a more milk or cream if needed. The mixture should be so thick that it holds in the balloon of a whisk, and slowly pours back into the bowl in an opaque ribbon. Pour a spoonful of glaze over each cake, gently nudging the glaze over the sides of the cake with the back of a spoon. Let the cakes stand until the glaze is firm, about 1 hour.
Meanwhile, tint a 2 oz. ball of marzipan with the copper brown gel food color. Knead well until a consistent hue is achieved. Repeat the process with another 2 oz. ball of marzipan and the moss green food color. If the marzipan is sticky, knead in a little confectioners’ sugar.
Roll out each piece of marzipan and stamp small flower shapes from the copper marzipan using the flower plunger cutter. Gently shape them using a fluted, pointed star fondant tool. Use the small leaf plunger cutter to stamp shapes from the moss green marzipan. A leaf veiner can be used to create leaf impressions in the marzipan, if desired.
When the mini cakes are firm, arrange flowers and leaves on top of each cake. When they are arranged correctly, use dot of leftover glaze to adhere them to the tops of the cakes (or you could use a water dampened art brush). Using cake decorator’s tweezers, press gold sugar pearls into the centers of each cake.
Place cakes in a large cake box or in a baking pan that is taller than the cakes’ height. Store loosely covered in plastic wrap in the refrigerator (an airtight container will cause the glaze to wrinkle – avoid this). Allow cakes to stand at room temperature for a few minutes before serving. This knocks a little of the chill off and the flavors will be well developed.
Notes
The work of building this cake can be spread out over a couple of days. The pumpkin sponge and cranberry filling can be made a day ahead of assembly. Marzipan decors can be made ahead of time and stored airtight for freshness.Cake layers will stay well-defined and sharp when refrigerated. If left at room temperature for more than a couple of hours, the cranberry filling will begin to soak into the bottom sponge.