Get yourself organized first! You will need all of the following: Your baked Chocolate Sponge Cake, the Soak, the Frosting, and the Chip Mixture ingredients. As well you will need a 6in cake ring and some acetate to assemble this cake.
Place your cooled sponge on the counter and, using a sharp paring knife, the back of a spoon, or a bench scraper, loosen the cake from the sides of the pan.
Place a piece of parchment or a baking mat on the counter and invert the cake onto it, giving the far edge of your overturned pan a sharp rap on the counter to release the cake. Peel off the parchment stuck to the cake and discard it.
Use your cake ring to stamp out 2 circles from the cake, one from the upper right-hand corner and one from the lower left-hand corner (or lower right-hand and upper left-hand corners), which will form the top and middle layer of the cake
Make sure to plan out your circles to make sure you know exactly where to stamp before completing this step — you can mark them lightly on your sponge using your cake ring. Use the ring to stamp out two half-circles from the remaining sponge, which will come together to make the bottom layer of the cake.
Clean the cake ring and place it on the 8-inch cardboard round, or any other cake board, platter, or parchment-lined pan (whatever will be easiest to transport the cake to the freezer).
Use 1 strip of 5-6″ tall acetate to line the inside of the cake ring.
Place the two half circles of cake together inside the ring, spongey (not browned) side up, and fill the gap between them with additional pieces of cake scrap. Use the back of your fingers to press the scraps together into a flat, even layer.
Using a spoon or a pastry brush, splash or brush half the Soak over the bottom layer of cake.
Spread one-fifth of the frosting in an even layer over the cake using the back of a small spoon that fits into the acetate collar, or a spoon you’ve bent into a ladle-like shape. Use figure-8 motions to spread the frosting evenly and try to not pick up your spoon as you work.
Sprinkle a third of the total Mini Semi-Sweet Chocolate Chips and of the ground up Peppermint candies evenly over the frosting. Anchor the chips into place in the frosting using the back of your fingers.
Use the back of a spoon to spread another fifth frosting as evenly as possible over the chips. You should see some chips peeking through the frosting.
Place your middle cake layer on top of the frosting, passing it through the acetate collar at an angle to help it nestle into place. Add some crumb scraps along the edges of your cake if you see any gaps or areas where frosting is coming up and press down with your fingers.
Repeat the process of splashing or brushing the layer with the remaining soak, spreading it with one-fifth of the frosting, sprinkling one-third of the chip/peppermint dust, and finishing with another fifth of the frosting.
Nestle the remaining cake round onto the frosting. Cover the top of the cake with the remaining frosting and add any desired visual effects like spikes, swirls, or a flat surface using a spoon, knife, or offset spatula
Garnish the frosting with the remaining chips and peppermint dust to your liking!
Transfer the cake to the freezer and freeze for a minimum of 3 hours (or overnight) to set the cake and filling. The cake will keep in the freezer for up to 2 weeks.
At least 3 hours before you are ready to serve the cake, pull the cake out of the freezer and slide off the cake ring. If you need to, use your fingers and thumbs to pop the cake out of the ring.
Gently peel off the acetate and transfer the cake to a platter or cake stand, or whatever you want to serve it on. Let it defrost for 2-3 hours. Wrapped well in plastic, the cake can be refrigerated for up to 5 days.
When the cake is fully thawed, slice and serve to lucky friends and family!