Preheat oven to 400*F (205*C).
Line potatoes on bottom and up sides of a greased 8 x 12-inch casserole dish. Bake uncovered for 10 minutes.
Brown beef in large chunks; drain. Place beef, broccoli, 1/2 can French fried onions and tomatoes in potato shell.
Combine soup, milk, 1/2 cup cheese, garlic powder and pepper; pour over beef mixture.
Bake, covered, for 20 minutes. Remove from oven and top with remaining cheese and onions; bake uncovered 2 to 3 minutes more, or until cheese has melted.