Cut three slices of cheese into four strips each; set aside. In a large bowl, combine egg, onion, tomato juice, oats, Worcestershire sauce, bouillon, garlic powder, and pepper. Add ground beef and mix well.
In a shallow baking dish, pat half of the meat mixture into an 8x4-inch loaf. Make a 1/2-inch-wide indentation down the center of the meat mixture. Arrange the cheese strips in the indentation. Shape remaining meat mixture over the top of the cheese strips; pinching edges to seal. (Loaf size should be 8x4x2 inches.)
Bake in a 350 degrees F oven about 1 hour or until no pink remains (thermometer inserted in the thickest part of the meat loaf registers 170 degrees F).
Cut remaining two cheese slices in half diagonally. Place on top of meat loaf. Bake about 3 minutes more or until cheese melts. Garnish with chopped tomato and snipped parsley, if desired. Makes 6 servings.