Culver's Restaurant Copycat Recipe
1 stick plus 6 tablespoons unsalted butter, at room temperature
2 onions, chopped
1 pound ground beef sirloin
6 soft hamburger buns, split
1/3 cup water
Preheat broiler. Melt 2 tablespoons of butter over medium heat in large cast iron skillet. Add onions and cook for 8 minutes. Add water, cover and continue to cook for about 15 more minutes which is when the onions should turn golden brown. Season with salt and pepper and transfer onions to bowl.
Divide meat into 6 separate portions. Flatten into thin patties. Wipe skillet and heat it over high heat. Add patties to skillet, smash them flat with a spatula and season with salt and pepper. Cook and then flip once. Each sides should cook for at least 3 minutes.
Toast buns under broiler. Put patties on the buns and top with 1/4 cup sauteed onions. Smear 2 tablespoons butter on the cut side of each bun. Put on top of burger and serve immediately. Makes 6 servings.