Heat the oil in a nonstick skillet over medium heat until hot, but not smoking. Add the onions and cook until they begin to soften, about five minutes.
Either heat a cast iron skillet on the stove over med/high heat or turn on your grill to high heat. Cook the burgers for about 3 mins on each side for medium rare.
Top with cheese after flipping in the last two minutes of cooking. Split open the buns and spread each half with the homemade ketchup, then top with the cheeseburgers, onions, bacon and fried eggs.