Instructions

• Divide the 12 tablespoons of softened butter for use: 2 tablespoons for cooking the onions, 2 tablespoons for cooking the patties, and the remaining 8 tablespoons (2 tablespoons per bun top) for the buns.
• In a large skillet over medium heat, melt 2 tablespoons butter. Add the chopped onion, 1 tablespoon water, and 1/4 teaspoon of the kosher salt. Cover and cook until the onion is tender, about 5 minutes.
• Reduce the heat to medium-low, remove the lid, and cook until the onions are translucent and just beginning to brown, about 3 more minutes. Transfer the onions to a plate, divide into 4 equal portions, and set aside.
• Divide the 1 pound ground beef into 4 equal portions. Gently shape each portion into a patty about 4½ inches wide and ½ inch thick.
• Sprinkle the patties evenly with the remaining 1/2 teaspoon kosher salt (so the total salt used = 3/4 teaspoon) and the 3/4 teaspoon ground black pepper. Refrigerate the patties for 15–30 minutes.
• While the patties chill, toast the 4 buns (split) until golden. After toasting, spread 2 tablespoons of the reserved butter on each bun top and set the buns aside.
• Return the same skillet to medium-high heat and add the remaining 2 tablespoons butter. When the butter is hot and shimmering, carefully add the patties to the skillet. Cook undisturbed for 3 minutes.
• Flip the patties and cook for 1 more minute. Place 1 slice of American cheese on each patty and cook an additional 20–30 seconds, until the cheese melts.
• Place each cooked patty on a bun bottom, top each with one quarter of the sautéed onions, then finish with the buttered bun top. Serve immediately.