Prepare the hamburger patties:

1. In a large mixing bowl, add ground beef, breadcrumbs, cheddar cheese, parsley, pickle juice, garlic powder, Worcestershire sauce (optional), and salt and pepper. Stir well with a spatula to combine everything together (or use your hands to press the ingredients together to evenly combine).
2. Shape the ground beef mixture into a firm ball. This helps the beef mixture bind together to yield firm patties. Cover the bowl with cling wrap and refrigerate for at least 1 hour or overnight.
3. Transfer the ground beef mixture onto a large piece of parchment paper. Flatten the ground beef with your hands into a square that is 1/2-inch thick (approximately an 8x8-inch square). You can also roll it out with a rolling pin.
4. Use a 4-inch wide circular mold (or the rim of a round bowl) to cut out 4 hamburger patties (1/4 pound each). Add the scraps evenly amongst the 4 patties.

Grill the hamburger patties:

1. Brush oil over the grill pan and heat pan over medium-high heat for 3 minutes until the oil starts to sizzle and shimmer. Place patties spaced apart on the grill and cook for 5 minutes on each side until the internal temperature for the patties reaches 160 F. It takes about 10 minutes total.

Assemble the hamburgers:

1. Slice the hamburgers and toast the slices on the grill, if desired.
2. On each hamburger bun, spread 1 tablespoon mayonnaise onto the bottom half of the bun. Top with a piece of lettuce and a grilled hamburger patty. Top the patty with 1 slice of tomato, 2 or 3 slices onions and sliced pickles. Add a tablespoon ketchup on the top half of the bun. Place the top half of the bun on top to assemble the hamburger.
3. Serve with a side of crispy french fries.