If frozen, thaw the 4 Beyond Burger patties. Place each thawed patty between two sheets of waxed paper and roll gently with a rolling pin to 1/4-inch thickness; do not press too hard.

Season both sides of the flattened patties with 1/2 teaspoon salt (total) and 1/4 teaspoon black pepper (total).

Preheat a grill to medium-high heat.

Spread the 1 tablespoon softened butter evenly on the cut sides of the 4 sesame hamburger buns. Toast the buns, cut-side down, in a skillet over medium heat until lightly browned. Set the toasted buns aside.

Grill the seasoned patties 2 to 3 minutes per side, flipping once, until browned and heated through. While cooking, sprinkle a light pinch of the extra salt onto each patty.

Divide the toppings evenly for assembly: 12 pickle slices (3 per burger), 8 tomato slices (2 per burger), 8 lettuce leaves torn into pieces (divide evenly), and the sliced onion rings (divide evenly). Also divide the 4 tablespoons ketchup and 4 tablespoons mayonnaise so each burger gets 1 tablespoon ketchup and 1 tablespoon mayonnaise.

Assemble each burger: place a toasted bottom bun on a plate, put a cooked patty on the bottom bun, spread 1 tablespoon ketchup onto the patty or bottom bun, top with 3 pickle slices, the divided onion rings, 2 tomato slices, and the divided lettuce pieces. Spread 1 tablespoon mayonnaise on the inside of the top bun.

Place the mayonnaise-spread top bun onto each burger and serve immediately.