(Batter for 4 mug cakes.)

4 coffee mugs (microwave safe)
½ cup sugar
½ cup butter, softened at room temperature
2 eggs, lightly beaten
1 teaspoon vanilla
1 cup flour
½ teaspoon baking powder
¼ teaspoon baking soda
pinch salt
red, orange, yellow, green, blue, food coloring

In a large bowl cream the sugar and butter together by hand until light and fluffy, about 3 minutes. Crack in an eggs, one at a time, mixing each well. Pour in vanilla. Beat for one minute until well combined. Mix dry ingredients carefully add to batter, just until combined.  Divide the mixture as evenly as you can between 5 bowls. Add a couple of drops of food coloring to each bowl; stir very gently.  Spoon the colors between the 4 mugs one spoonful at a time. Lay the different colored cake batter on top to create a marbled effect. Microwave  for 3 minutes.