In a skillet over medium heat, cook the bacon until crispy. Remove and drain on paper towels, reserving 2 tablespoons of bacon grease in the skillet.

In a bowl, mix mayonnaise, minced garlic, lemon juice, and a pinch of salt and pepper to make the garlic aioli. Set aside.

Divide the ground beef into 4 equal portions (about 4 ounces each). Form each portion into a loose ball without compacting it too much.

Heat the skillet with the reserved bacon grease over high heat. Once hot, place the beef balls in the skillet and immediately smash them down with a spatula to form patties. Cook for about 2-3 minutes until a crust forms, then flip and cook for another 2 minutes. Season with salt and pepper.

During the last minute of cooking, place 2 slices of bacon on each patty and top with a slice of cheese if desired. Cover the skillet to melt the cheese.

Toast the hamburger buns in the same skillet until golden brown.

Assemble the burgers by spreading garlic aioli on the bottom bun, adding the lettuce, tomato, and the bacon cheeseburger patty. Top with the other half of the bun.

Serve immediately.