Melt butter in a heavy sauce pan. Whisk in flour until smooth. Cook while stirring 3 - 4 minutes.
Add milk slowly until desired consistency. Mixture will thicken as it cooks.
NOTE: Less milk will yield a thick or heavy sauce, more milk will yield a thin or light sauce, a moderate amount of milk will yield a moderate sauce. For a good all purpose cheese sauce, just stir in a cup of shredded cheese until melted.
Yields: