You will need to work quickly for this recipe, so get all of your ingredients together as well as a whisk. In a pot over medium heat, add the oil and heat it until it is sizzling but not smoking.
Add the flour and spices to the hot oil and whisk well.
Pour in the stock, tomato paste, oregano, vinegar, and a pinch of salt and pepper.
Whisk constantly until the mixture thickens and then take off the heat immediately and keep whisking until it cools.
Store in a sealable container until you are ready to use it to top your enchiladas.