Close up picture of sliced meatloaf with ketchup on top. This 5-Ingredient Easy Meatloaf recipe may be short on ingredients, but it is loaded with flavor. The lack of breadcrumbs means you don't have them soaking up the juices, so the meat stays moist - and it's gluten free too! Parmesan cheese, onion, egg, ketchup, salt, and pepper are all that go into this yummy loaf of goodness!