Making a Simple Rue

The basis to many recipes, especially (but not limited to) anything with a ‘white’ or cream sauce, is a simple rue (or roux). Most simply put, it is flour, to thicken the sauce, which has been sautéed in butter to get rid of the ‘floury’ taste that it would give the food if you added it directly.
When making a rue sauce, the general rule of thumb is 1 tablespoon of flour and 1 tablespoon of butter (or other oil for the calorie-conscious) for every cup of liquid. This makes a fairly thick sauce, just about perfect for brown gravy. Use a higher or lower rue-to-liquid ratio as needed.