Mushroom Swiss Burger Onions (Printable Version)

Juicy beef burger with sautéed mushrooms, Swiss cheese, and caramelized onions on a toasted bun.

# What You'll Need:

→ Caramelized Onions

01 - 2 large yellow onions, thinly sliced
02 - 2 tablespoons unsalted butter
03 - 1 tablespoon olive oil
04 - 1/2 teaspoon salt
05 - 1/2 teaspoon sugar

→ Sautéed Mushrooms

06 - 9 ounces cremini or button mushrooms, sliced
07 - 1 tablespoon unsalted butter
08 - 1 tablespoon olive oil
09 - 1/4 teaspoon salt
10 - 1/4 teaspoon black pepper
11 - 1 teaspoon fresh thyme leaves (optional)

→ Burger Assembly

12 - 1.3 pounds ground beef (80/20 blend recommended)
13 - 1 teaspoon salt
14 - 1/2 teaspoon black pepper
15 - 4 slices Swiss cheese
16 - 4 burger buns, split and toasted
17 - 2 tablespoons mayonnaise (optional)
18 - 2 cups fresh arugula or lettuce leaves

# Method:

01 - Heat butter and olive oil in a large skillet over medium-low heat. Add sliced onions, salt, and sugar. Cook, stirring occasionally, until onions are golden and caramelized, about 18 to 20 minutes. Remove from heat and set aside.
02 - In the same skillet, warm butter and olive oil over medium-high heat. Add mushrooms, salt, pepper, and thyme if using. Sauté until browned and moisture evaporates, approximately 6 to 8 minutes. Remove from heat and set aside.
03 - Divide ground beef into four equal portions and shape into patties slightly larger than the buns. Season both sides with salt and pepper.
04 - Preheat grill or skillet to medium-high heat. Grill patties 3 to 4 minutes per side for medium doneness or desired level. During the last minute of cooking, place a slice of Swiss cheese on each patty and cover to melt.
05 - Optionally spread mayonnaise on bottom buns. Layer with arugula or lettuce, followed by the cheese-topped patty, then a generous portion of sautéed mushrooms and caramelized onions. Cap with the top bun.
06 - Serve immediately while warm.

# Chef's Tips:

01 -
  • The caramelized onions add a natural sweetness that makes you forget fast food burgers even exist.
  • Mushrooms and Swiss cheese create this umami depth that feels restaurant-quality but takes barely any extra effort.
  • You can prep everything ahead, so dinner comes together faster than you'd think.
02 -
  • Don't rush the onions—low heat and patience turns them sweet; high heat just burns them and tastes bitter.
  • Letting your ground beef rest at room temperature for 10 minutes before cooking makes burgers cook more evenly and stay juicier.
  • If your mushrooms release liquid, let it cook off completely or your burgers get soggy.
03 -
  • Make a well in the center of each patty with your thumb before cooking—it helps them cook evenly and stay juicy instead of puffing up into a dome.
  • Let your cooked burgers rest for a minute or two before serving so all those delicious juices redistribute instead of running onto your plate.

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