Mix the ground beef, oats, eggs, tomato puree, salt, mango pepper and onion in a large bowl.
Shape into a loaf and place in a baking dish.
Bake at 400 degrees for 25 minutes.
Prepare the gravy mix according to package directions and pour half the gravy over meat loaf.
Bake for 25 minutes longer.
Slice the meat loaf and serve with remaining gravy.