Swiss Mushroom Burger

Swiss Mushroom Burger
Ingredients:
For the Burger Patties:
1 lb (450g) ground beef (80% lean)
1 tsp salt
1/2 tsp black pepper
1/2 tsp garlic powder
1/2 tsp onion powder
1 tbsp Worcestershire sauce (optional)
For the Mushroom Topping:
2 cups sliced mushrooms
1 tbsp butter