Preheat oven to 350 F. Grease bottom and sides of three 8-inch round cake pans. Mix together the dry ingredients with wire whisk until well combined. In a separate bowl, combine all wet ingredients. (Note: 10 drops of blue and 15 drops of pink for a dark purple, or 24 drops of red and 16 drops of blue for a medium purple.) Gradually add wet ingredients into the dry ingredients, stir until well combined. Pour into greased and floured round cake pans. Bake for 20 to 25 minutes until toothpick inseted near the center comes out clean. Let it cool for 15 minutes and remove from pans on wire rack to allow cool completely.
Cream together the cream cheese and butter. Add the confectioners' sugar and vanilla. Beat until smooth and creamy. Spread between layers and over top and sides of a cake.