Blend all ingredients in a food processor or blender until well combined and smooth. Season with salt and pepper to taste.
Sauce will last up to one week stored in an airtight container in the refrigerator.
Be sure to have all of the ingredients measured out and near the stove. This sauce comes together very quickly.
Heat the oil in a small saucepan over medium heat. Add the flour and whisk together for a few seconds. Whisk in the chili powder, garlic powder, cumin, salt and pepper. Whisk in the tomato paste. The mixture will darken a bit, cook a minute until fragrant.
Gradually add in the stock, whisking the entire time. Increase the heat to medium-high, bring the sauce to a boil and then to a simmer. Mix in the vinegar. Cook 5-7 minutes. Whisk often to remove lumps and to make a smooth sauce. Sauce will appear thin at first and will thicken as it cooks. Add ground red pepper now to taste if you want a spicy sauce. Test the thickness with a spoon. It will continue to thicken as it cools.
Transfer the sauce to a heat proof container to cool or use immediately for enchiladas. Enchilada sauce can be refrigerated and used within 5 days or you can freeze it for up to 3 months.
