Add hot water (as hot as your tap will go, but not boiling) to a measuring cup. Pour the salt into the water.
Add about 15 drops of food colouring to the hot water and salt mixture.
Stir this mixture well, for 30 seconds to 1 minute, until the salt has partially dissolved.
Step 2: Combine wet and dry ingredients
In a separate microwave safe bowl, add the cream of tartar to the flour and mix well.
Add the water and salt mixture to the flour mixture and stir, making sure to scrape out any undissolved salt from the measuring cup.
Add 1 teaspoon of cooking oil.
Stir well until the mixture is completely combined.
Step 3: Microwave and stir
Place bowl in the microwave and cook on high power for 60 seconds.
Remove from the microwave and stir. There will be some light areas with raw dough. Stir for at least 1 minute, working everything together. If you still see raw, light coloured dough after stirring for a minute, return it to the microwave 20 seconds at a time until it's cooked through. Do not overcook it or the dough will be harder.
Remove your playdough from the bowl and flatten it out on the counter to help it cool more quickly.
Step 4: Enjoy and play!
Your playdough is complete!
Video
Notes
Microwave times may vary depending on your microwave. We found 1 minute was perfect for us. There were still light areas with raw dough when we pulled it out of the microwave, but after stirring and working it together, the heat cooked the raw doughy areas and it became perfectly cooked.