In the skillet you just fried something in; Pour off all but about 1/4 cup of fat.
Add 1/4 cup less 1 tablespoon flour.
Begin stirring, and add 1/4 teaspoon salt & 1/4 teaspoon pepper.
If you are careful to keep stirring as it cooks, it will begin to make a paste.
Add 2 cups of milk, and keep stirring over med. low heat till it thickens.
When you can see the bottom of the pan as you stir, it's done.