Pepperoni Pizza Casserole - With greens

1 lb extra lean ground beef 1/3 cup green bell pepper , chopped 1/3 cup onion , chopped 1/4 teaspoon garlic powder 15 ounces pizza sauce 4 ounces mushrooms ,[...]

1 lb ground beef 1 (16 ounce) can tomato sauce 1 (4 ounce) can mushrooms 2/3 cup milk 1 (8 ounce) package mozzarella cheese , shredded 1 teaspoon garlic salt[...]

1 large loaf Italian bread, cut into about 1/2-inch cubes (you might want to refrigerate before cutting, it makes slicing easier) 1 (10 ounce) box frozen[...]