1. Preheat oven to 350F. Grease and flour a 10-inch round cake pan and a 1/2-quart ovenproof bowl. Prepare cake mix according to package directions. Place 2 1/2 cups of batter into the bowl; pour remaining batter into cake pan. Bake until cakes are golden and a toothpick inserted in centers comes out clean, 40-45 minutes for the bowl and 20-25 minutes for the pan. Transfer cakes to wire racks; cool 10 minutes. Invert onto racks; invert bowl cake again, flat side up. Cool completely.
2. Add blue food coloring, one drop at a time, into 1 cup of frosting, until desired color is reached. Add yellow food coloring, one drop at a time, into remaining frosting, until desired color is reached. Cover both and set aside.
3. Trim top of both cakes to make level. Place 10-inch cake on a serving platter; using a knife, trim a 1/2-inch piece from edge of cake at an angle to create a slightly beveled hat brim. Click here for a helpful photo. Frost 10-inch cake using some of the yellow frosting. Place bowl cake flat side down in center of frosted 10-inch cake and cover with yellow frosting.
4. Gently drag the tines of a fork from the base of the bowl cake to the outer edge of the 10-inch cake, creating the effect of a ridged hat brim. Continue until the hat brim is completely covered with ridges.
5. Spoon the blue frosting into a pastry bag fitted with a basket-weave tip. Pipe 2-3 lines around the bottom of the hat crown to create a ribbon effect. Pipe additional lines to create tails of ribbon on the hat brim. Sprinkle confetti candy over the brim.
Not a NESTLÉ®-tested recipe.