Heat olive oil over medium heat until the flour mixture sizzles when it touches the pan. Add the flour mixture and whisk constantly for about 1 minute, until fragrant and darker in color.
While whisking constantly, add in the tomato paste and slowly pour in the broth.
Simmer the mixture gently for 5-8 minutes until the sauce has thickened a bit. Remove from the heat and whisk in vinegar.
Use in recipes as needed.
Notes
For gluten-free enchilada sauce, you can substitute in a gluten-free flour blend. If you prefer to spice this up, add some red pepper flakes or hot sauce during step 3. Either way, taste and adjust as desired. This recipe is easily doubled - it will keep in the fridge for up to a week or can be frozen for later use. Adapted from Cookie + Kate and Gimme Some Oven.
Recipe by Uproot Kitchen at https://uprootkitchen.com/2020/03/21/enchilada-sauce/