Step 1

FOR THE CAKE: Adjust oven rack to middle position and heat oven to 350 degrees. Grease and flour three 8-inch round cake pans and line bottoms with parchment paper. Whisk egg whites, champagne, vanilla, and food coloring together in bowl.

Step 2

Using stand mixer fitted with paddle, mix flour, sugar, baking powder, and salt on low speed until combined, about 30 seconds. With mixer running, add butter, 1 piece at a time, until incorporated and mixture resembles moist crumbs. Add all but 1/2 cup egg white mixture and beat until just combined. Increase speed to medium-high and beat until light and fluffy, about 1 minute. Add remaining 1/2 cup egg white mixture in slow stream. Scrape down bowl and beat batter on medium-high speed until well combined, about 15 seconds.

Step 3

Divide batter evenly among prepared pans and smooth tops with rubber spatula. Bake until toothpick inserted in center comes out clean, 21 to 25 minutes, rotating pans halfway through baking. Let cakes cool in pans on wire rack for 10 minutes. Remove cakes from pans, discarding parchment, and let cool completely on rack, about 2 hours.

Step 4

FOR THE CURLS: Place candy in bowl and microwave at 50 percent power, stirring often, until melted, 2 to 4 minutes. Pour melted candy into 4 by 4-inch container at least 1 inch deep. Refrigerate until just set, 15 to 30 minutes. Let block soften slightly at room temperature, about 5 minutes. Remove block from container and run blade of vegetable peeler along width of block to form curls.

Step 5

TO ASSEMBLE: Place 1 cake layer on cake plate or pedestal. Top with half of pastry cream. Place second cake layer on top. Top with remaining pastry cream. Place third cake layer on top. Spread buttercream in even layer over top and sides of cake. Top with pink chocolate curls. Serve.