Heat oil in a medium saucepan over medium heat. Add the flour and stir constantly for about 1 minute (don’t burn). Add the remaining ingredients and stir to combine.
Bring to a low boil, then turn the heat down to low and cook for 5 to 10 minutes, until the sauce thickens slightly and is smooth. Remove from heat.
Serve immediately or store in an airtight container up to 3 days refrigerated.
Notes
Tips for Storing
Room temperature: This sauce should not sit out at room temperature for more than 2 hours. Move it to the fridge or freezer once it has cooled.
Refrigerator: Store in an airtight container or jar in the fridge for up to 5 days. The flavors actually deepen overnight, so it is even better the next day.
Freezer: This enchilada sauce freezes beautifully for up to 3 months. Pour it into a freezer-safe zip bag or ice cube tray for easy portioned use.
Reheating: Warm gently on the stovetop over medium-low heat, whisking occasionally. If it has thickened up in the fridge, just add a splash of broth or water and whisk until smooth.