Mushroom Swiss Burger

Ingredients

• •1 1/2 lb ground beef
• •Salt and pepper to taste
• •1 onion, thinly sliced
• •2 cups mushrooms, sliced
• •3 tbsp butter, divided
• •4 slices Swiss cheese
• •4 hamburger buns

Steps

1. 1.Melt 1 tbsp butter in a skillet over medium-low heat and cook the onion, stirring occasionally, for 20-25 minutes until deeply caramelized and golden brown - low and slow is what turns onions sweet instead of just soft.
2. 2.Sauté the mushrooms in the remaining butter over medium heat until golden, then season with salt and pepper off the heat - salting mushrooms before cooking draws out their moisture and keeps them from browning.
3. 3.Form the ground beef into four patties, season generously with salt and pepper, and press a shallow dimple into the center of each - the dimple keeps the patties from puffing into a dome as they cook.
4. 4.Cook the patties for 4-5 minutes per side, topping each with Swiss cheese during the last 2 minutes so it melts fully.
5. 5.Top each patty with the caramelized onions and sautéed mushrooms.
6. 6.Serve on buns.