1 cup sour cream
½ cup mixed finely chopped fresh chives, dill and parsley
⅓ cup ketchup
¼ cup buttermilk
¼ cup pickle relish
1 tbsp. Worcestershire sauce
Salt and pepper
2 ¼ lbs. 80% lean ground beef
Olive oil, for drizzling
4 slices yellow American cheese
4 slices yellow sharp cheddar
4 sesame-seed hamburger buns or sesame brioche buns, halved and lightly toasted
Sliced dill pickles
1 small white onion, finely chopped
Thinly sliced iceberg or little gem lettuce
In a medium bowl, mix the sour cream, herbs, ketchup, buttermilk, relish and Worcestershire; season the sauce with salt and pepper.
Heat a cast-iron skillet, griddle or grill over medium-high. In another medium bowl, season the beef and form 8 very thin, large patties. Drizzle the skillet with oil; add 4 patties and cook, turning occasionally, 6 to 7 minutes. Top 2 of the patties with a slice of each of the cheeses during the last minute or so of cooking. Top each with another cooked patty to melt the cheese; transfer to a plate. Repeat with the remaining patties and cheese.
Top the bun bottoms with the pickles and onion, the double patties, then the lettuce. Top with some of the sauce and the bun tops.