Heat oven to 375 degrees. Grease pie plate, 9 X 1 1/4 inches. Cover potato slices from scalloped potato package with boiling water in 2 1/2 quart bowl; stir in salt. Let stand uncovered 15 minutes; drain thoroughly. Toss potatoes with melted margarine and 1 egg. Press potato mixture against bottom and siside of pie plate. Bake 10 minutes.
Mix ham,broccoli, 1/2 cup of the cheese, 2 eggs and the onion. Heat 2 tablespoons margarine in 2 quart saucepan until melted; stir in Sauce Mix from scalloped potato package, the milk and mustard. Heat to boiling over medium heat, stirring contantly. Boil and stir 1 minute. Fold into ham mixture; spoon into potato shell. Bake uncovered 30 minutes; sprinkle with remaining cheese. Bake until cheese is melted, about 5 minutes longer. Let stand 5 minutes before serving.