Add butter or bacon grease to a sauce pan over medium-high heat.
When the butter or bacon grease has completely melted, add the flour and stir constantly for one minute.
Add the canned enchilada sauce, chicken (or beef) stock, salt, and chili powder.
Increase heat to high and bring the sauce to a boil, then reduce heat to medium-low and simmer, uncovered, until the sauce has thickened (approximately 10-15 minutes).
Reduce heat to low and keep warm until ready to serve.
Notes
*Note: If you are sensitive to spice, use ¼ teaspoon of chili or chipotle chili powder and taste before adding more.