12 slices white bread, frozen
3/4 pound Wisconsin sharp cheddar cheese, sliced
1 package (10 ounces) frozen chopped broccoli, cooked and drained
2 cups cooked ham, finely diced
6 eggs, slightly beaten
3 1/2 cups milk
2 tablespoons instant minced onion
1/2 teaspoon salt
1/4 teaspoon dry mustard
1/2 cup (2 ounces) shredded Wisconsin sharp cheddar cheese
Cut twelve circles with a doughnut cutter from bread slices. Fit the scraps of bread, without crusts, in bottom of buttered dish. Place cheese in layer over bread; add layer of broccoli and ham. Arrange bread doughnuts and holes on top. Combine next five ingredients; pour over ham. Cover and refrigerate 6 hours or overnight.
Bake, uncovered, at 350° F for 55 minutes, until firm and golden. Sprinkle shredded cheese on top and bake 5 minutes longer. Let stand for 10 minutes before cutting in squares to serve.