In a large bowl combine the flour, salt and cream of tartar. Mix to combine.
In a separate container, combine the 1 cup of boiling water, food colouring and oil.
Add the boiling water mixture to the flour mixture and mix. Be careful the mixture will be very hot!
Add the 0.5 cups of boiling water in small increments until you have reached the desired consistency. Note: You may not need to add all of the water. If you are using a stand mixer, add the water as the mixer is turning.
Add additional food colouring, if desired. If kneading by hand, let the mixture cool before you pick it up, protect your counters and hands from staining by laying a sheet of wax paper down and wearing gloves. Knead, knead, knead.
Knead it until all its smooth and soft! If using a stand mixer let it continue to mix on medium-high until it starts to form a dough ball.
Optional: Add your favourite extracts or essential oils.