This is a recipe that I have actually made. My MIL liked it so well that she served it on holidays quite a few times. The recipe is found in a Woman's Day Collectors Cookbook and also the Farm Journal Vegetable Cookbook.
Beans Au Gratin
1 box each green beans, lima beans and wax beans (it is hard to find frozen wax beans I usually use canned)
4 tablespoons butter or margarine, divided use
2 tablespoons flour
1 teaspoon salt
Dash Worcestershire sauce
1 cup medium cream
1/2 cup grated Parmesan cheese
Cook beans separately according to package directions. Drain. Mix lightly and put in shallow baking dish. In a medium saucepan melt 2 tablespoons butter; stir in flour, salt, pepper and Worcestershire. Add cream and cook stirring frequently until thickened. Pour over beans. Dot with remaining butter and sprinkle with cheese. Bake in a 375 degree oven until hot and browned. Makes 6 servings.