BANANA FLIP CAKE

Steps:

• Line two greased 15x10x1-in. baking pans with waxed paper and grease the paper. Set aside., In a large bowl, combine the cake mix, pudding mix, milk and eggs. Beat on low speed for 30 seconds; beat on medium for 2 minutes., Spread batter into prepared pans. Bake at 350° until a toothpick inserted in the centers come out clean, 12-15 minutes. Cool for 5 minutes before inverting onto wire racks to cool completely. Gently peel off waxed paper., Meanwhile, in a small saucepan, whisk flour and milk until smooth. Bring to a boil; cook and stir until thickened, about 2 minutes. Remove from the heat; cover and cool to room temperature., In the bowl of a heavy-duty stand mixer, cream the butter, shortening and sugar until light and fluffy. Beat in vanilla. Add milk mixture; beat on high until fluffy, 10-15 minutes., Place one cake on a large cutting board; spread top with frosting. Top with remaining cake; sprinkle with confectioners' sugar. Cut into squares. If desired, top with whipped topping and sliced bananas. Refrigerate leftovers.