In a mixing bowl, combine the flour, salt, and cream of tartar. Mix well to ensure the ingredients are evenly distributed.
In another bowl, combine water, oil, and food coloring separately.
Pour the dry ingredient mixture into the bowl of the slow cooker.
Next, add the wet ingredient mixture. Mix everything thoroughly.
Position a tea towel under the lid. Cover and cook for 45-60 minutes on high, stirring frequently during the first 30 minutes of cooking time, and occasionally thereafter.
The dough will be ready when it forms and no longer adheres to the sides of the slow cooker.
To check if it’s done, take out a small portion, shape it into a ball, and let it cool in the freezer for a few minutes. If it doesn’t stick to your fingers when handled, it’s ready. You can then return the test ball to the rest of the dough.
Remove the entire mixture from the slow cooker, knead it, and place it in a container to cool.
Once the play dough is cool and colored, it’s ready to be used! Store it in an airtight container or ziplock bag when not in use to keep it fresh and pliable.
Remember, this play dough is for playing, not for eating. Enjoy your homemade red play dough!