Ingredients
Scale
- 1/2 cup mayonnaise
- 1 1/2 tablespoons ketchup
- 1 tablespoon pickle relish
- 1 teaspoon sugar
- 3/4 teaspoon white vinegar
- 1 tablespoon butter
- 1 tablespoon canola oil
- 3 cups finely chopped yellow onions
- 3/4 teaspoons salt, divided
- 4 tablespoons water, or as needed
- 1 lb ground chuck or 80% lean ground beef
- 1 teaspoon canola oil
- 1/2 teaspoon black pepper
- 3 tablespoons mustard
- 8 slices American cheese
- 4 hamburger buns, toasted
- 16 dill pickle chips
- 4 slices tomato
- 2 leaves iceberg lettuce, torn
Directions
- Stir together mayonnaise, ketchup, relish, sugar, and vinegar in a small bowl for the sauce.
- Heat butter and 1 tablespoon oil in a nonstick skillet over medium heat. Add onions and season with ΒΌ teaspoon salt. Cook, stirring occasionally, until onions are tender and golden brown, about 20 minutes. When skillet starts to become dry, add 1 tablespoon water. Continue cooking, stirring often, adding more water as needed, 1 tablespoon at a time, until onions are very soft, deeply browned, and jammy, 10 to 15 minutes more. You may not need to use all the water. Remove from heat.
- Shape beef into 8 patties, about 3/8-inch-thick and 4 inches in diameter. Sprinkle with pepper and remaining 1/2 teaspoon salt.
- Heat 1 teaspoon oil in a large cast-iron skillet over medium-high heat. Working in batches as needed, add patties to skillet. Spread 2 teaspoons mustard over top of each patty. Cook until browned, about 2 minutes per side. Top patties with cheese and onions. Cook, covered, about 30 seconds, until cheese is melted. An instant-read thermometer inserted into the center should read at least 160 degrees F (70 degrees C). Layer patties to create 4 stacks.
- Spread sauce onto bun bottoms. Fill each bun with 4 pickles, a tomato slice, lettuce, and 1 patty stack.