Add vegetable oil to a large skillet and heat over medium high heat.

Add the ground beef and brown breaking it up as it cooks.

When the meat is almost done add the onion and continue cooking until the meat and onions are fully cooked.

Add the tomato sauce, ketchup, yellow mustard, salt, and pepper. Stir to combine with the meat and simmer for 10 to 20 minutes or until the sauce has thickened to your liking.