Rocket Ship Cake

1 . Stage

Preheat oven to 350 degrees F. Butter a 9-by-13-inch baking pan. Line bottom with parchment or waxed paper; butter lining. Dust with flour; tap out excess. Set aside.

2 . Stage

Sift together flour, baking powder, and salt into a medium bowl; set aside. Stir together milk and vanilla in a small bowl; set aside. Put butter in the bowl of an electric mixer fitted with the paddle attachment; beat on medium speed until creamy, about 2 minutes. Add sugar in a slow, steady stream; mix until pale and fluffy, scraping down sides of bowl as needed, about 3 minutes.

3 . Stage

Reduce speed to low; add flour mixture in 3 batches, alternating with the milk mixture and beginning and ending with the flour (do not overmix). Set aside.

4 . Stage

Beat egg whites in the clean bowl of an electric mixer fitted with the whisk attachment until stiff peaks form. Fold one-third of whites into batter. Fold in remaining whites in 2 batches.

5 . Stage

Pour batter into prepared pan, and smooth with an offset spatula. Bake until cake is springy to the touch and a cake tester inserted into center comes out clean, 35 to 40 minutes. Let cake cool in pan on a wire rack 15 minutes. Run a knife around sides of cake to loosen; invert onto wire rack. Reinvert cake; let cool completely, right-side up, before decorating. (Cooled cake can be frozen, wrapped in plastic wrap, up to 2 days.)

6 . Stage

With a serrated knife, trim top of cake to make it flat. Halve cake horizontally to make 2 layers. Spread 1 cup buttercream over bottom layer; place second layer back on top. Cut cake into components using template. Arrange on a platter or foil-covered board to form rocket shape. If desired, cut board slightly larger than assembled cake shape before wrapping in foil.

7 . Stage

Spread 1 1/4 cups buttercream in a thin layer over entire cake; refrigerate until firm, about 20 minutes. Meanwhile, prepare buttercream for decorating. Assemble 5 pastry bags with couplers. Tint 3/4 cup buttercream each red and blue, and 1/2 cup gray; transfer each to a pastry bag. Fill another bag with 1/4 cup each red, orange, and yellow buttercream; fit with an Ateco #233 multi-hole tip. Fill last bag with 1/2 cup plain buttercream.

8 . Stage

Frost cake with a smooth layer of buttercream. Fit gray bag with an Ateco #4 plain tip; outline rocket. Add designs: a filled-in nose, a round window, or the outline of a flag. Sprinkle rocket nose, bottom, and window with sanding sugar.

9 . Stage

Fit red, white, and blue bags with Ateco #18 star tips; pipe stripes. Use an Ateco #16 star tip for flag. Pipe a white star border around bottom edge of cake. For letters, use an Ateco #8 plain tip. Pipe "flames" out of bottom of rocket using bag of multicolored buttercream. If desired, attach figurine with licorice. Chill until ready to serve, up to 4 hours.