Preheat your grill or skillet over medium-high heat.

Season the ground beef with salt and pepper, then divide into 4 equal portions. Form each portion into a patty slightly larger than your buns.

Place the bacon slices on the grill or skillet. Cook until crispy, about 3-4 minutes per side. Transfer to a paper towel-lined plate to drain.

Grill or cook the patties for about 4 minutes on one side. Flip the patties, add a slice of cheese to each, and cook for another 3-4 minutes for medium doneness.

While the patties cook, toast the hamburger buns cut side down on the grill or skillet until lightly toasted, about 1 minute.

To assemble, spread mayonnaise on the bottom buns. Add a lettuce leaf, a slice of tomato, a cheese-topped patty, and two slices of bacon. Add ketchup if using, then cover with the top bun.

Serve immediately.