Cream of Anything Soup

2 T butter 
2 T flour 
1 C milk 
1/4 tsp salt 
1/4 tsp pepper

In heavy saucepan, melt butter. Sprinkle in flour and stir to incorporate. Cook over medium-low for 2-3 minutes, stirring constantly. Slowly whisk in milk (remove from heat to do it). Add salt and pepper. Return to heat and allow to bubble and thicken, again stirring constantly. Can use in a recipe immediately or store in fridge for later use.  You can add any choice of flavor to this: sauteed mushrooms, celery, etc.