Add Flour and cream of tartar all at once to above.
Cook over medium heat, stirring constantly until well mixed and dough forms a ball, (this should only take a couple minutes).
Remove from heat once the dough forms into a ball.
Cool on a clean baking sheet, kneading the dough as soon as it is cool enough to handle.
Cool completely, and let your kids play away!
(On occasion, I've mixed in a matching essential oil to enhance the fruity scent if I only have one package of a Kool-aid flavour on hand.) Store this Play Dough in a resealable plastic baggy or plastic container.
It should last for a couple months, depending on how often your children play with it.