In a large bowl, combine hash browns, cheddar cheese soup, egg, 1 tsp salt and 1/2 tsp pepper. Press firmly into a greased pizza pan. Bake at 450°F for 20-25 minutes. Meanwhile, fry beef and onion until meat is no longer pink; drain. Stir in flour until blended. Add tomato soup, 1/2 tsp salt, garlic powder and 1/8 tsp pepper. Bring to a boil; cook and stir for 2 minutes. Sprinkle crust with 1 cup cheese. Top with beef mixture and remaining cheese. Bake 5 minutes until cheese is melted. Let stand 5-10 minutes before cutting.