Cut a hole 2-1/2 or 3 inches in diameter from the center of bread slice. Reserve center round. In a small shallow flat dish combine one of the eggs, milk, salt, and pepper. Dip bread slice and center round in egg mixture.
In a medium skillet melt margarine or butter over medium heat. Cook dipped bread slice and center round in margarine about 1 minute on each side or until light golden brown. Drop remaining egg in center of slice and cook until egg is almost of desired doneness. Turn over and top with cheese. Cook about 1 minute more or until cheese is slightly melted. (For an egg cooked sunny-side up, cook for 2 minutes, and cover skillet after adding cheese slice.) Garnish with avocado and tomato slices, if desired. Makes 1 serving.