1. 1 lb (450g) ground beef (80% lean)
2. 1 tsp salt
3. 1/2 tsp black pepper
4. 1/2 tsp garlic powder
5. 1/2 tsp onion powder
6. 1 tbsp Worcestershire sauce (optional)

For the Mushroom Topping:

1. 2 cups sliced mushrooms
2. 1 tbsp butter
3. 1 tbsp olive oil
4. 1/2 cup finely chopped onion
5. 2 cloves garlic, minced
6. 1/4 cup beef broth or white wine (optional)
7. Salt and pepper to taste

For Assembly:

1. 4 slices Swiss cheese
2. 4 hamburger buns, toasted
3. Lettuce leaves
4. Tomato slices
5. Pickles (optional)
6. Mayonnaise, mustard, or your favorite condiments

1. Prepare the Burger Patties:
2. In a large bowl, gently mix together the ground beef, salt, black pepper, garlic powder, onion powder, and Worcestershire sauce if using.
3. Divide the mixture into 4 equal portions and shape them into patties. Use your thumb to create a small indentation in the center of each patty to help it cook evenly.

Cook the Mushrooms:

1. Heat the butter and olive oil in a large skillet over medium heat.
2. Add the chopped onions and cook until they become translucent (about 2-3 minutes).
3. Add the sliced mushrooms and cook until they release their moisture and start to brown (about 5-7 minutes).
4. Stir in the minced garlic and cook for an additional minute.
5. If desired, deglaze the pan with beef broth or white wine and cook until the liquid evaporates. Season with salt and pepper to taste.

Cook the Burger Patties:

1. Heat a grill or skillet over medium-high heat.
2. Cook the burger patties for about 4-5 minutes per side, or until they reach your desired level of doneness. During the last minute of cooking, place a slice of Swiss cheese on each patty and cover the skillet to melt the cheese.

Assemble the Burgers:

2. Toast the hamburger buns if desired.
3. Spread mayonnaise, mustard, or your favorite condiments on the bottom half of each bun.
4. Place a lettuce leaf on each bun, followed by a slice of tomato and pickles if using.
5. Add the cooked burger patty with melted Swiss cheese on top of the vegetables.
6. Spoon the sautéed mushrooms over the cheese.
7. Top with the other half of the toasted bun.