Italian Stuffed Meat Loaf
["1 lb. ground beef", "1 c. Quaker oats (quick or old fashioned)", "1 (15 1/2 oz.) jar spaghetti sauce", "1/2 c. chopped onion", "1/3 c. grated Parmesan cheese", "1 egg", "1 Tbsp. Worcestershire sauce", "1 tsp. pepper", "1/3 c. any or mixture of the following: sliced mushrooms, sliced ripe olives, shredded Mozzarella cheese, shredded zucchini"]
["Note:", "Set aside additional 1/2 cup Mozzarella cheese and 1/8 cup sliced olives for garnish."]
["ground beef", "oats", "spaghetti sauce", "onion", "Parmesan cheese", "egg", "Worcestershire sauce", "pepper", "mushrooms"]