I got this simple recipe here and the whole process probably only took about 30 minutes. Plus, aside from the food coloring, I had everything in my pantry. Here is the recipe:
(Also, you should try this recipe for edible diy fingerpaint. It uses a similar list of ingredients and a great natural, non-toxic solution for toddlers, and super fun.)
1 cup flour
1 cup warm water
1/2 cup salt
1 Tablespoon vegetable oil
2 Tablespoons cream of tartar
Mix all of the ingredients in a pot, and stir over low heat. The dough will thicken until it resembles mashed potatoes.When the dough pulls away from the sides and clumps in the center remove the pan and allow to cool until you can handle it comfortably. Place dough on a clean surface knead until it is smooth. Divide the dough into balls for coloring.
Make a small dent in each ball of dough and drop food coloring in each hole. Fold the dough working the food coloring in. Use plastic wrap or gloves to protect your hands. Though, I did get lazy and started working the dough with my bare hands. The food coloring came out with a good wash. Once the food coloring is worked through, it is safe to handle. Keep adding coloring until the desired color is achieved.
Store in an airtight containers.