Mushroom Swiss Burger Onions (Printable)
Beef patty topped with sautéed mushrooms, Swiss cheese, and caramelized onions in a toasted brioche bun.
# What You'll Need:
→ For the Burgers
01 - 1 ½ lbs ground beef (80/20 blend recommended)
02 - 1 tsp kosher salt
03 - ½ tsp black pepper
→ For the Caramelized Onions
04 - 2 large yellow onions, thinly sliced
05 - 2 tbsp unsalted butter
06 - 1 tsp sugar
07 - Pinch of salt
→ For the Sautéed Mushrooms
08 - 8 oz cremini or button mushrooms, sliced
09 - 1 tbsp olive oil
10 - ½ tsp fresh thyme leaves (optional)
11 - Salt and pepper, to taste
→ For Assembly
12 - 4 slices Swiss cheese
13 - 4 brioche burger buns
14 - 2 tbsp mayonnaise (optional)
15 - 1 cup arugula or lettuce leaves (optional)
# How-To Steps:
01 - In a large skillet over medium heat, melt the butter. Add sliced onions, sugar, and a pinch of salt. Cook, stirring occasionally, for 15–20 minutes or until onions are golden brown and soft. Set aside.
02 - In another skillet, heat olive oil over medium-high heat. Add mushrooms and cook for 5–7 minutes until browned and tender. Season with salt, pepper, and thyme (if using). Remove from heat.
03 - In a bowl, gently mix ground beef with salt and pepper. Form into 4 equal patties, pressing a small indentation in the center of each to prevent puffing during cooking.
04 - Heat a grill or skillet over medium-high heat. Cook the patties for 3–4 minutes per side for medium doneness. In the last minute of cooking, top each patty with a slice of Swiss cheese and cover to melt.
05 - Lightly toast brioche buns on the grill or in a toaster.
06 - Spread mayonnaise on the bottom buns (if using). Add arugula or lettuce, then place the burger patties on top. Pile on the sautéed mushrooms and caramelized onions. Top with the upper buns and serve immediately.
# Expert Tips:
01 -
- The caramelized onions become almost jammy adding this incredible sweet depth that balances the rich beef
- Swiss cheese melts beautifully while bringing a nutty flavor that ties everything together
02 -
- Don't rush the caramelized onions they need low steady heat to develop that deep sweetness.
- Let the patties rest for a minute after cooking so the juices redistribute instead of running out immediately.
03 -
- Sprinkle a little Worcestershire sauce into the mushrooms while they cook for an extra layer of savory depth.
- If your brioche buns are fresh skip the toasting for the bottom bun so it absorbs some of those burger juices.