Mix the patty ingredients together in a small bowl. Reserve 2 Tablespoons of the ketchup for the patty toppings. Mix the ingredients together with your hands and form into 4 even patties.
Heat in a large skillet over medium heat. Place the patties in the heated skillet. Brown each side for approximately 5-7 minutes (do not smash the patties down when you flip them). Then add 1 cup of water to the skillet and continue cooking the patties until the juices run clear. Spoon the reserved ketchup on top of each Pattie (approximately 1/2 tablespoon on each patty).
Toast the buns and serve the patties on the buns with the lettuce, tomatoes and sliced onions.
Serve warm and enjoy!
Notes
Refrigerate any leftover patties in an airtight container for up to 5 days.