Preheat oven to 350 degrees F (175 degrees C). Saute onion in butter
Soak the bread in the milk. Add eggs, cheese, salt, , milk, cheese, oats and salt. Then add the ground beef, mixing gently with a fork. Use a scoop to measure into muffin tins that have been sprayed with nonstick spray. Mix ketchup and dry mustard and top each meatloaf muffin. Bake for about 25 mins or until internal temp is 160.