Turn devil's food cake mix into this easy candy corn cake for Halloween.
Cut parchment to fit in the bottom of two 8-inch round baking pans. Coat with nonstick cooking spray. Prepare cake mix according to package directions for two 8-inch cakes, replacing water with buttermilk and using vegetable oil and eggs. Pour evenly into pans and bake at 350 degrees for 34 to 38 minutes, until a toothpick inserted in the center comes out clean. Cool in pans on baking racks 15 minutes. Remove from pans, remove parchment and cool completely.
Meanwhile, prepare frosting. Using a stand mixer or hand mixer, combine butter, confectioners' sugar and milk. Beat on low until just combined, then on high 3 to 5 minutes, until fluffy. Mix orange food coloring into 1 1/2 cups of the frosting and yellow food coloring into 2/3 cup of the frosting. Keep remaining 1/3 cup of the frosting white. Transfer ¾ cup of the orange and all the yellow and white frosting to individual piping bags fitted with a star tip.
Heat heavy cream in a small pot until simmering. Place chopped chocolate in bowl of a stand mixer. Pour cream over chocolate and stir until smooth. Let cool 5 minutes. Beat with whisk attachment on high 10 minutes, until fluffy. Let ganache stand 10 minutes.
Trim layers to make each flat. Place one cake layer on a stand. Spread reserved orange frosting evenly over top.
Place second cake layer on top, then spread ganache evenly around the sides. Pipe white frosting in a circle, starting from center of cake, followed by remaining orange frosting and finally the yellow frosting until it reaches the edges. Press candy corns in to base of cake, alternating direction with each one. Slice into wedges. (Each wedge will resemble a piece of candy corn from the top.)