MIXING A CAKE RECIPES

Steps:

• Sift the flour, sugar, cocoa, baking soda, baking powder, and salt into the bowl and mix until combined.
• In another bowl, combine the buttermilk, oil, eggs, and vanilla.
• With the mixer on low speed, slowly add the wet ingredients to the dry. With mixer still on low, add the coffee and stir just to combine, scraping the bottom of the bowl with a rubber spatula. 
• Pour the batter into two 8-inch round prepared pans and bake for 30 to 40 minutes at 350°F, until a cake tester or toothpick comes out mostly clean (not wet).
• Cool in the pans for about 10 minutes, then turn them out onto a cooling rack and cool completely.

Steps:

• Heat oven to 350°F. Grease and flour 2 (8-inch) round cake pans or spray with baking spray. Set aside.
• Combine flour, baking powder and 1/4 teaspoon salt in bowl; set aside.
• Beat sugar and 1 cup butter in another bowl at medium speed, scraping bowl occasionally, until creamy. Add eggs, 1 at a time, beating well after each addition. Add 1 tablespoon vanilla; mix well. Add flour mixture alternately with milk, beating at low speed after each addition, just until mixed.
• Divide batter evenly among 6 bowls with about 3/4 cup each. Tint cake batters red, orange, yellow, green, blue and purple. Spread red and orange batter into prepared pans. Bake 8-10 minutes or until toothpick inserted into center comes out clean. Cool 3 minutes; remove from pans to cooling rack. Cool completely. Meanwhile, wash pans; grease and flour pans. Repeat with remaining colors until all cake layers are baked.
• Beat 2 cups butter in medium bowl at medium speed until creamy. Gradually add powdered sugar and 1/4 teaspoon salt alternatley with whipping cream and 1 tablespoon vanilla, beating at low speed until well incorporated. Beat at medium speed until smooth and creamy. Remove 2 cups frosting; set aside. Divide remaining frosting evenly among 6 bowls with about 1/3 cup each. Tint frostings red, orange, yellow, green, blue and purple. Set aside.
• Place purple cake layer onto serving plate, bottom-side up. Frost top with 1/4 cup white frosting. Place blue cake layer over frosting; frost with 1/4 cup white frosting. Continuing adding green, yellow, orange and red layers in that order, frosting with 1/4 cup white frosting between each layer. Frost outside of cake with remaining white frosting. This layer of frosting will be thin and cake will be visible through frosting. Once frosted, refrigerate cake 30 minutes. (This is called a crumb coat and will prevent crumbs from interfering when piping rosettes.)
• Place each tinted frosting into individual resealable plastic food bag; push frosting to one corner. Cut off 1/2 inch from tip of corner. Place 18-inch-long piece of plastic food wrap onto counter surface. Pipe each color onto plastic wrap to form wide 12-inch horizontal lines (using all of frosting) that are touching.
• Gently roll frosting lines into one large log using plastic wrap. Snip tip off one end of plastic wrap. Place cut-side down into piping bag fitted with size 1M open-star tip. Pipe rainbow rosettes onto cake beginning with middle of top of cake and working out and down sides so the most vibrant colors are on top of cake.