In a liquid measuring cup, stir together water and food coloring and pour into a medium saucepan. Add flour, salt, cream of tartar, and cooking oil and whisk well to combine.

Cook mixture over medium heat for 2 to 3 minutes, stirring constantly, just until dough begins to pull away from sides of pan. Remove from heat and cool to touch.

Use for pretend play. Although this playdough is nontoxic and safe to eat, I don't recommend it!

To store, place in quart size zipper freezer bag, remove excess air, and place in refrigerator. Will keep for several weeks if sealed well.