Cook potatoes until tender and mash until smooth. Beat in salt, pepper, nutmeg and 2 Tbl butter.
Spread 2 rbsp butter in a 9-inch pie plate. Dust with half of bread crumbs, then cover with 1/2 of the potatoes. Arrange cheese and ham over it and cover with the remaining potatoes. Sprinkle with remaining bread crumbs and dot with remaining butter.
Bake at 400°F for 25 minutes or until it browns. Cut into wedges.