1 c. milk
2 tbsp. butter
2 tbsp. all purpose flour
1 tsp. prepared mustard
1/2 tsp. salt
1/4 tsp. white pepper
3 med. potatoes, peeled and thinly sliced (about 1 1/2 c.)
1 1/2 c. cooked diced ham
1 tsp. minced onion
1/4 c. shredded Cheddar cheese

Pour milk into 2-cup glass measure. Cook on high (maximum power) 2 minutes. Set aside. Place butter in 2-cup glass measure. Cook on high (maximum power) 1 minute stir in flour. Cook on high (maximum power) 1 minute. Briskly stir hot milk, prepared mustard, salt and pepper into butter. Set aside.

Place potatoes in 1 1/2 quart microproof casserole. Add ham and onion. Pour white sauce over ham and potato mixture. Stir to combine. Cover with waxed paper. Cook on high (maximum power) 20 to 22 minutes stirring twice during cooking time. Sprinkle with cheese. Cover and let stand 10 minutes or until cheese is melted.