Preheat oven to 350 degrees. Cook broccoli until just tender. Drain, slice lengthwise into thin strips. Arrange sliced broccoli on bottom of buttered casserole. Salt and pepper. Pour 1/3 of Sauce Parisienne over broccoli. Sprinkle with mushrooms. Arrange sliced chicken over mushrooms and cover with remaining sauce. Sprinkle thickly with Parmesan cheese. Drizzle melted butter over cheese. Bake for 30 minutes, or until top is golden brown.

The Sauce Parisienne recipe is available here.