Step 1
Preheat oven to 350°F. Grease and flour three 8x2-inch round cake pans.
Step 2
In the bowl of an electric mixer fitted with the paddle attachment, cream butter and sugar until light and fluffy. Add the eggs, one at a time, and the vanilla. Continue mixing until well incorporated.
Step 3
In a separate bowl, combine flour, baking powder, and salt. With the mixer at low speed, alternately add flour mixture and milk. Ending the process with flour mixture. Mix about 1 minute. Add sour cream and mix until well incorporated.
Step 4
Fold in rainbow sprinkles. Pour the batter evenly into the prepared pans and bake for 30-35 minutes or until a toothpick inserted in the middle comes out clean.
Step 5
Remove from oven and let the cakes cool in the pan for 20 minutes. Remove from pan and set in a cooling rack. Cool completely.
Step 6
Assemble cake with cream cheese frosting. Place one cake layer, bottom side up, on a plate. Spread ½ cup cream cheese frosting. Top with second layer, bottom side up, and ½ cup cream cheese frosting. Top with remaining layer, bottom side up. Reserve about ½ cup of frosting for rosettes decoration on top. Ice the cake with the remaining frosting. Decorate with rosettes by using a pastry bag fitted with the 1M tip.
Step 7
Carefully, using your hands, apply rainbow sprinkles to the bottom third of the cake. Sprinkle extra rainbow sprinkles on top.
Step 1
In large bowl, beat cream cheese, butter and vanilla until creamy. Gradually beat in powdered sugar.
Step 2
To make a decorator frosting, prepare one-half recipe of the above. Beat in 1/4 to 1/2 cup additional powdered sugar. Color as desired with food color; use in a decorator tube.
For the frosting: to thin, add a few drops of milk; to thicken, add additional powdered sugar.
