This is the closest you'll get to from-scratch butter cake taste when using a mix. The flavors in this cake will bring back memories of birthday parties of yesteryear--light yellow layers, fluffy chocolate frosting and that essential glass of cold milk. You couldn't keep your hands out of the mixing bowl as a child and you won't be able to as an adult! Reprinted with permission from THE CAKE MIX DOCTOR by Anne Byrn (Workman Publishing, 1999)
Place a rack in the center of the oven and preheat the oven to 350 degrees. Generously grease two 9-inch round cake pans with solid vegetable shortening, then dust with flour. Shake out the excess flour. Set the pans aside.
Place the cake mix, milk, melted butter, eggs and vanilla in a large mixing bowl. Blend with an electric mixer on low speed for 1 minute. Stop the machine and scrape down the sides of the bowl with a rubber spatula. Increase the mixer speed to medium and beat 2 minutes more, scraping the sides down again if needed. The batter should look well blended. Divide the batter between the prepared pans, smoothing it out with the rubber spatula. Place the pans in the oven side by side.
Bake the cakes until they are golden brown and spring back when lightly pressed with your finger, 27 to 29 minutes. Remove the pans from the oven and place them on wire racks to cool for 10 minutes. Run a dinner knife around the edge of each layer and invert each onto a rack, then invert them again onto another rack so that the cakes are right side up. Allow them to cool completely, 30 minutes more.
Meanwhile, prepare the Fluffy Chocolate Frosting.
Place one cake layer, right side up, on a serving platter. Spread the top with frosting. Place the second layer, right side up, on top of the first layer and frost the top and sides of the cake with clean, smooth strokes.
Place this cake, uncovered, in the refrigerator until the frosting sets, 20 minutes. Cover the cake with waxed paper or place under a glass cake dome and store at room temperature for up to 4 days. Or freeze it, wrapped in aluminum foil, for up to 6 months. Thaw the cake overnight in the refrigerator before serving.