Apart from opening the presents, the highlight of any birthday party is almost always the cake. Use our rainbow-fish cake template to create a spectacular chocolate cake covered with meringue buttercream frosting studded with colorful candy-wafer scales.
Dark Chocolate Cake; makes one 12 1/2-by-17 1/2-inch cake
1 1/2 cups (3 sticks) unsalted butter, melted, plus more for baking pan
4 cups all-purpose flour, plus more for baking pan
3 cups sugar
1 1/2 cups Dutch-process cocoa
1 teaspoon salt
1 tablespoon baking powder
1 1/2 teaspoons baking soda
2 large whole eggs, room temperature
2 large egg whites, room temperature
2 teaspoons pure vanilla extract
2 2/3 cups strong, hot coffee
1 1/2 recipe Swiss Meringue Buttercream
Rainbow Cake How-To
To Make the Cake
1. Preheat oven to 325 degrees. Line a 12 1/2-by-17 1/2-by -1-inch buttered baking pan with parchment. Dust bottoms and sides with flour; tap out excess. Set aside.
2. Place all the ingredients except the hot coffee in the bowl of an electric mixer fitted with the whisk attachment. Mix on low speed until combined, about 1 minute. Slowly add the coffee. Mix until smooth, about 1 minute. Pour batter into prepared baking pan; smooth top with an offset spatula.
3. Bake until a cake tester inserted into the middle comes out clean, 45 to 50 minutes. Transfer baking pan to wire rack to cool. Invert cake onto a cutting board. Do not remove parchment. Refrigerate, uncovered, for at least 1 hour.
To Assemble the Cake:
1. Tint 2/3 cup buttercream with royal-blue and sky-blue food coloring gel until bright blue. Cover and set aside. Remove cake from refrigerator. Remove and discard parchment paper.
2. Follow instructions on our template, and cut out all five of the cake's sections, taking note of which is which.
3. Place six parchment strips around the perimeter of a large serving platter (the parchment will protect platter from buttercream and can easily be removed when cake is finished). Using a large offset spatula, transfer body of fish to the parchment lined serving platter.
4. Line up tail halves so the two narrowest ends are together. Using a serrated knife, trim away 1/3 inch from the inside edge of each half. Apply 2 tablespoons buttercream to the inside edge of the top half of the tail. Press the long sides of both tail halves together to form the tail. Apply 1 tablespoon buttercream to the body of the fish's tail end, and attach the tail. Apply 2 tablespoons buttercream to curved side of the dorsal fin, and attach to top of body. Apply 1 tablespoon buttercream to short end of the pelvic fin, and attach to bottom of body.
5. Using an offset spatula, ice cake with 2 cups buttercream to give the cake a crumb coat. This thin layer of buttercream will seal the cake. Start from the center, and work out, making sure to push the buttercream over the sides of the cake. Smooth the buttercream. Later, you'll cover the crumb coat with more icing, so it doesn't have to be perfectly smooth at this point. Transfer cake to refrigerator, and chill to set the buttercream, about 30 minutes.
6. Remove cake from refrigerator. Use remaining white buttercream to completely cover outside of cake, smoothing top and sides. Using the tip of a paring knife, outline the face, tail, and fins. Comb all sides of cake, top of tail, and fins decoratively with decorating comb or serrated knife.
7. Starting where the tail attaches to the body and continuing to the outline of the face, overlap the candy wafers to form scales on the top of the fish. If rainbow pattern is desired, keep colors separate. Continue to overlap assorted random colors to cover the face with scales. Using a pastry bag fitted with a #11 Ateco tip, pipe a mouth and eyes.
8. After the cake is frosted and the wafers are laid in place, a cake-decorating comb is the ideal tool to finish the decorating. Draw the comb along the solid portions of frosting on the tail and fins to create the same lined pattern as on an actual fish. If you don't have a cake-decorating comb, a serrated knife will work almost as well. Should you make a mistake, simply smooth the frosting over, and start again.
Rainbow-Fish Cake Template
We offer the following file in a PDF format, to make the details clear and printable. If you have trouble downloading the file, or if you'd like to upgrade to the most recent version of Acrobat Reader, you can obtain the software from Adobe's website.