Combine all ingredients except the food coloring: the flour, cream of tartar, and salt into a small sauce pan.
Cook on medium heat, stirring constantly. After a few minutes the liquid mixture should start to solidify. Keep cooking and mixing until the dough forms a ball. Remove dough from heat and place on the counter.
Allow dough to cool down enough to be handled.
Gentle knead the dough for about 3 minutes. The dough should no longer be sticky.
Divide the dough into half. Place each half in a ziploc bag and add the food coloring. Knead the food coloring into the dough in the bag until you've achieved the color consistency you desire. Store in an airtight container for up to 3 months.