I think this originally came from "Best of Bridge". It is a great way to use leftover ham.
- Preheat oven to 400 degrees F.
- Cook onion in butter.
- Blend in flour, salt, and pepper.
- Add milk slowly, stirring continuously, cook until thick.
- Remove from heat.
- Add cheese and stir until it melts and is well blended.
- Add ham and potatoes and mix together.
- Pour into a casserole dish, sprinkle with crumbs.
- Bake at 400 degrees F for 30 minutes.