Add cake mix, vanilla, eggs, oil and water to mixing bowl.
Mix according to package instructions.
Separate the mix into three bowls
Add 1-2 drops of food color per bowl and mix until well incorporated.
Line cupcake tin with wrappers.
Add one tsp of each color to the liners until 3/4 full.
Bake for 15-18 min
Let cool.
Frosting:
Make your favorite vanilla frosting.
Dye it the same 3 colors as the batter.
Place each color in a 12 inch piping bag.
Drop a 1M tip into a 16 inch piping bag.