In a large mixing bowl, combine ground beef, ranch seasoning mix, and chopped bacon. Season with salt and pepper. Mix gently and form into 4 equal patties, making a small indentation in the center of each.
Preheat grill or skillet over medium-high heat. Cook patties for 4-5 minutes on each side until desired doneness. During the last minute, add shredded cheddar cheese on top of each patty to melt.
In a small bowl, mix mayonnaise, Dijon mustard, and Worcestershire sauce to create ranch dressing.
Toast hamburger buns until golden brown. Spread ranch dressing on the bottom half, add the cheesy patty, and top with lettuce and tomato slices. Place the top half of the bun on each burger and serve immediately.