2 tbsp. chopped onion
1/4 c. butter
1/4 c. flour (all-purpose)
1 tsp. salt 1/2 tsp. dry mustard
Dash of pepper
1 1/2 c. milk
2 c. shredded cheddar cheese
2 c. cubed cooked ham
6 c. cubed cooked potatoes

Saute onion in butter in a large saucepan until tender. Add flour and seasonings, stirring until smooth. Cook 1 minute, stirring constantly. Gradually add milk; cook over medium heat, stirring constantly until thickened and bubbly.

Add 1 1/2 cups cheese, stirring until cheese melts. Add ham and potatoes, tossing gently. Spoon into a 2-quart greased shallow baking dish. Bake uncovered at 350 degrees for 25 minutes. Sprinkle with remaining 1/2 cup cheese; bake additional 15 minutes.