Melt butter in a small pan over medium low heat.
Whisk flour into melted butter. Allow to brown for a minute or two, while whisking/stirring.
Whisk in soy milk, tomato paste, and spices.
Continue whisking over medium heat until thickened into a sauce. (It will firm up quite a bit as it cools).***
Store leftovers in the fridge. See notes below for reheating instructions.