Preheat the oven to 350 degrees F and line 2 baking sheets with parchment paper. Set aside.

In the bowl of an electric mixer, beat egg whites until foamy. Add the cream of tartar and beat until fluffy.

Add the sugar very slowly, about 1 tablespoon at a time while still beating.

Add the vanilla extract and continue beating until the meringue is shiny.

Evenly divide the meringue into 3 medium-sized bowls. Add 2-3 drops of purple food coloring to one bowl, 2-3 drops of green coloring to the second bowl and 2-3 drops of yellow coloring to the third bowl. Take a toothpick or the tip of a sharp knife and gently swirl the color into the meringue. It is very important that you DO NOT STIR.

Meringues may be dropped by the tablespoonful onto the parchment paper lined baking sheets, or piped onto the sheets using a pastry bag, leaving a 1-inch space between each cookie.

Place baking sheets in the preheated oven and turn the oven off.

Leave the cookies undisturbed in the oven for at least 2 hours.