In a large mixing bowl, combine the ground beef, ranch seasoning mix, onion soup mix, garlic powder, and black pepper. Mix until just combined; do not overwork the meat.

Form the mixture into 8 equal patties, making a slight indentation in the center of each patty to prevent puffing during cooking.

Preheat a grill or skillet over medium-high heat. Cook the patties for about 4-5 minutes on each side, or until they reach your desired doneness.

During the last minute of cooking, place a slice of cheddar cheese on each patty and cover to melt.

In a small bowl, mix together the mayonnaise, Dijon mustard, and Worcestershire sauce. This will be your special sauce.

Toast the hamburger buns on the grill or in a toaster until golden brown.

Assemble the burgers by spreading the special sauce on the bottom bun, adding the patty with melted cheese, and topping with lettuce, tomato, and pickles. Place the top bun on and serve.