2 tbsp. chopped onion
1/4 c. butter
1/4 c. flour
1 tsp. salt
1/2 tsp. dry mustard
Dash of pepper
1 1/2 c. milk
2 c. shredded Cheddar cheese
1/4 lb. ham, cubed or more to taste
6 c. cooked potato slices

Preheat oven to 350 degrees. Saute onion in butter. Blend in flour and seasonings. Gradually add milk. Cook and stir until thick; add cheese and stir until melted. Fold in potatoes and ham. Turn into casserole dish. Bake for 30 minutes.

OPTIONAL: Add chopped broccoli or any favorite vegetables to make this a one-dish dinner.