2 beef bouillon cubes, dissolved in 2 c. hot water

Mix with wire whisk until smooth:

1 stick melted butter
1/2 c. flour

Add:

2 tsp. dry mustard
2 tsp. Worcestershire sauce
2 c. milk
1 lb. Velveeta, cubed
1/2 lb. American cheese

Place in a double boiler and stir constantly until desired consistency. If it becomes too thick, slowly add cold milk.