Separate the batter into three bowls, dividing evenly. Add drops of food coloring to each bowl to create a yellow batter, a pink batter, and a blue batter (I used two drops of yellow, three drops of pink, and six drops of blue). Spoon the batter into the prepared pans and spread evenly. Bake 25-30 minutes, or until the top springs back when touched lightly and a toothpick inserted in the center comes out clean. Remove and let cool completely.