In a bowl, cream butter and sugar until light and fluffy, 5-7 minutes. Add eggs, 1 at a time, beating well after each. Combine flour, baking powder and salt; add alternately with milk to creamed mixture. Mix well. Combine cocoa, water and vanilla; stir in 2 cups cake batter.
Pour into a greased and floured 9-in. round baking pan. Add orange extract, zest and food coloring to remaining batter. Pour into two greased and floured 9-in. round baking pans. Bake at 350° for 30 minutes or until cake tests done. Cool for 10 minutes before removing from pans to wire racks.
In a bowl, beat all frosting ingredients until smooth. Place 1 orange cake layer on a cake plate; spread with 1/2 cup frosting. Top with chocolate layer; spread with 1/2 cup frosting. Top with second orange layer. Frost the sides and top of each.
Microwave chocolate and cream on high 1-1/2 minutes or until blended, stirring once. Stir until smooth; let cool 2 minutes. Slowly pour over cake, letting glaze drizzle down sides. Garnish with candy corn.