Simmer onions in margarine until tender. Place in a 2-quart casserole. Top with cheese and pepper. Heat soup, milk and soy sauce, stirring till blended. Pour over onions and, using a knife, stir gently. Overlap bread slices in a ring. Bake at 350 for 15 minutes. Push bread slices down under sauce and bake 15 minutes longer. Makes 6-8 servings.