Preheat oven to 375°F. Coat a
2-quart casserole with cooking spray and arrange half of the sliced potatoes on the
bottom, overlapping.
In a medium bowl, combine ham, bell
pepper, and scallions. Evenly scatter over potatoes and top with remaining potato
slices
and sprinkle with cheese.
In a small saucepan, melt margarine
and blend in flour and mustard. Slowly add milk and continue to stir over medium heat
until sauce thickens; mix in black pepper and paprika. Pour sauce evenly over potatoes
and ham. Top with breadcrumbs.
Cover and bake for 45 minutes;
uncover and continue to bake for an additional 30 minutes or until potatoes are fork
tender and golden brown.