12 prepared mini graham cracker crusts
3 cups sweetened condensed milk
1/2 cup sour cream
3/4 cup key lime juice (about 15 key limes)
1 tablespoon grated lime zest
Preheat oven to 350 degrees F.
In a medium bowl, combine condensed milk, sour cream, lime juice, and lime zest. Mix well.
Separate in to four equal portions and add 5 to 7 drops of a different color food coloring to each.
Pour mixtures into graham cracker crusts (3 of each color)
Bake in preheated oven for 5 to 8 minutes, until tiny pinhole bubbles burst on the surface of pie.
Refrigerate pies until they are chilled.
Using a paint brush and different colors of food coloring add the symbol for pi.