In a large bowl, combine the ham, onions, green pepper, cream of mushroom soup, cheddar cheese, mayonnaise, Parmesan cheese, and bread crumbs. Mix well.
Pour mixture into a 9x13 inch baking dish.
Bake in preheated oven for 30 minutes, or until bubbly and lightly browned.
Interesting Facts
This casserole can easily be made ahead of time and refrigerated until ready to bake.
The Parmesan cheese adds a nice flavor to the casserole.