In a pan, heat 1 tablespoon of olive oil over medium heat.
Add sliced mushrooms with a pinch of salt and sauté until golden brown. Set them aside once done.
Mix ground beef with garlic powder, onion powder, salt, and black pepper in a bowl.
Form the mixture into four even patties for your burgers.
In the same skillet, melt 2 tablespoons of butter over medium heat.
Sear the patties for about 3-4 minutes on each side or until cooked to your liking.
Place a slice of Swiss cheese on each patty during the last minute of cooking.
Allow the cheese to melt thoroughly over the patties.
Toast the brioche buns in the skillet until lightly browned and warm.
Assemble the burgers by placing the patty with melted cheese onto the bottom bun, topping with sautéed mushrooms, and covering with the top bun.