In a skillet over medium heat, cook the bacon until crispy. Remove and drain on paper towels, then crumble into pieces.

In the same skillet, drain excess bacon fat, leaving about 1 tablespoon. Add the ground beef, season with salt and pepper, and cook until browned, about 6-8 minutes. Drain excess fat if necessary.

In a small bowl, mix together mayonnaise, ketchup, and mustard to create a sauce.

To assemble the bowls, divide the shredded lettuce among four bowls. Top each with cooked ground beef, crumbled bacon, diced avocado, cherry tomatoes, red onion, and shredded cheddar cheese.

Drizzle the sauce over each bowl and serve immediately.