2 tbsp. butter
2 tbsp. flour
1 tsp. salt
1/2 tsp. dry mustard
1 (1 lb. 12 oz.) can green beans
2 tsp. minced onion
1 1/3 c. half and half
1/2 c. grated Parmesan cheese

Melt butter, blend in flour, mustard, salt and onion. Stir in cream and cook over medium heat until mixture comes to a boil. Stir in cheese and heat through. Drain beans and add to sauce. Heat again. But DO NOT BOIL.