- 1 1/2 ground sirloin (80% lean)
- 1 small onion--2 tbsp. grated, the remainder finely chopped
- 1 tablespoon plus 1 tsp. Worcestershire sauce
- Kosher salt and black pepper
- 2 tablespoons butter
- 1 clove garlic, crushed
- 1/3 cup ketchup
- 1/3 cup creme fraiche or sour cream
- 3 tablespoons sweet or dill pickle relish
- 2 tablespoons chopped tarragon
- 8 slices yellow cheddar or yellow American cheese
- 4 soft burger rolls or brioche rolls, very lightly toasted
- 1 1/2 cups chopped romaine hearts
- 1 ripe tomato, seeded and chopped
- 8 thin dill pickle slices
Heat a cast-iron skillet or griddle pan over medium-high.
In a medium bowl, combine the beef, the grated onion and about 1 tbsp. Worcestershire sauce; season with salt and pepper. Form into 4 patties, thinner in the centers for even cooking. In a small saucepan, melt the butter over medium heat. Add the garlic, swirl 1 minute, then remove the garlic butter from the heat.
In a small bowl, stir the ketchup, creme fraiche, relish, tarragon and about 1 tsp. Worcestershire sauce until blended; season the sauce.
Cook the patties, turning occasionally and basting with the garlic butter as they cook, until browned, about 8 minutes. During the last minute or so of cooking, top each patty with 2 slices of cheese, stacking askew to form an eight-pointed star. Tent the pan loosely with foil to melt the cheese.
Scatter the finely chopped onion on the bun bottoms. Top with the hot patties, lettuce, tomato and pickles. Slather the bun tops with the sauce and set in place.