Mix the flour, salt and cream of Tartar in a saucepan.
Add the oil and stir.
Mix the water and food coloring, if using, then gradually blend into the mixture. You will need to use more natural coloring than you would with chemical food dyes.
Cook over moderate heat, stirring, until mixture is stiff and leaves the sides of the pan clean.
Set aside until cool enough to handle, then knead gently on a work surface until smooth.
Store in an airtight container.