Prepare the patties: Portion the ground beef into four equal segments. Form each segment into a patty approximately 1/2-inch thick. Season both sides with salt and pepper.
Create the sauce: In a small bowl, combine mayonnaise and ranch seasoning until thoroughly mixed. Set aside for later use.
Toast the buns: Apply butter to the inner sides of each hamburger bun. Toast them in a skillet over medium heat until they achieve a golden brown color.
Cook the patties: Preheat a skillet or grill to medium-high heat. Prepare the patties by cooking them for 3 to 4 minutes on each side, or until they achieve your desired level of doneness. In the final minute of cooking, place a slice of cheddar cheese on each patty to allow it to melt.
Assemble the burgers: Spread the ranch mayonnaise on the bottom bun. Layer with lettuce, pickles, the cooked patty topped with melted cheese, bacon, crispy fried onions, and finish with the top bun.
Serve immediately: Accompany with your preferred side dishes and enjoy your meal.