1 small onion, chopped
2 tbsp. butter
2 tbsp. flour
1 1/2 c. warm beef broth or water with a bouillon cube dissolved in it
1 cube beef bouillon, if needed

Sauté onion in butter in a saucepan until tender. Stir in flour and cook over low heat for a minute or 2. Add warm liquid slowly while quickly stirring. Stir until smooth and cook over low to medium heat until the gravy starts to boil and thicken. You can add more liquid as needed to make the gravy as thick as you wish. Reduce to low and simmer for about 5 minutes to cook out the flour flavor. Taste and add any salt or pepper.

Tips:

If you use a bouillon cube, be sure to dissolve it completely in the liquid.

If you use pan juices or drippings, be sure to use a gravy separator to remove any excess fat.

Be sure to add warm liquid to the butter/flour mixture to make it easier to stir out any lumps.