- 1 1/2 pounds ground beef chuck
- About 1/4 cup Worcestershire sauce
- 3 tablespoons grated onion
- Coarse salt and pepper
- 1 tablespoon vegetable oil
- 4 deli slices (not too thin) Emmentaler cheese
- 3 tablespoons butter
- 1 pound white mushrooms, sliced
- 1 shallot, finely chopped
- 1/3 cup dry sherry
- 1 cup sour cream
- 1/4 to 1/3 cup buttermilk
- 1/4 cup finely chopped dill, parsley, chives and thyme
- 1 tablespoon fresh lemon juice
- 1 tablespoon hot sauce
- 1 clove garlic, grated
- 4 brioche or other soft rolls, split
Preheat a cast-iron skillet or griddle pan over medium-high heat. Combine the chuck Worcestershire, onion, salt and lots of pepper. Form into 4 patties (thinner at the center and thicker at the edges for even cooking). Add oil to the hot pan, add the patties and cook, turning once for 8-10 minutes for medium-rare to medium. Top the patties with the cheese, folded to fit the burgers, during the last 2 minutes of cooking.
Meanwhile, in a separate skillet, melt the butter over medium heat. Add the mushrooms and cook until browned, about 12 minutes. Add the shallot, season with salt and pepper and cook for 2-3 minutes more. Deglaze the pan with the sherry and remove from heat.
In a bowl, stir together the sour cream, buttermilk, herbs, lemon juice, hot sauce and garlic; season with salt and pepper.
Put the cheeseburgers on the roll bottoms and top with the mushrooms. Slather the roll tops with the dressing and set into place.