You can use two 9-inch round pans or a 13 x 9-inch pan or cupcake pan.
Buttercream Icing: In large bowl, combine 3 cups of the confectioners'
sugar, butter, shortening, vanilla and 4 tablespoons of milk. Beat until smooth.
Add remaining confectioners' sugar and beat until fluffy. Add more milk as needed
to reach spreading consistency.