Form 4 burger patties and season liberally with salt and pepper on the outside.
Cook the bacon and place aside on paper towels to remove excess grease. Slice the onion so you get 4 thick slices. In the same pan using the leftover grease from the bacon, add your sliced onions and cook until they're slightly browned on each side. Set aside.
In a cast iron skillet (or sauté pan) add about 1/2 tablespoon of vegetable oil. When the skillet is hot--add patties.
Assemble each burger with one slice of onion, 2 slices of bacon and a drizzle of the spicy ketchup.
Tip: I don't believe in messing with quality meat so I never add any egg or breadcrumbs to my burgers...just be liberal with the salt and pepper and you'll get all the natural taste you need!
Tip: When cooking burgers, do NOT push down on them--all you'll get is dry burgers. Don't worry...you will get a great sear if you leave them alone!