This classic Mushroom Swiss Burger Recipe combines tender beef patties with melty Swiss cheese, golden mushrooms, and caramelized onions for one epic burger.
Craveable Mushroom Swiss Burgers
When I crave a burger, it’s usually something classic, like a Double Bacon Cheeseburger, but if I’m feeling the urge to venture out, my first stop is always a Mushroom Swiss Burger.
Mushrooms and Swiss cheese are a combo I find hard to resist. I love a gooey Mushroom Swiss Grilled Cheese or a Portobello Mushroom Sandwich, but I don’t think there’s any place I love this duo more than piled on top of a juicy burger.
While mushroom and Swiss makes a fine pair, I don’t think it’s quite complete without the addition of caramelized onions. The three of these together is the Holy Trinity of burgers, adding plenty of umami, creaminess, and a hint of sweetness.
Today, I’ll show you how to make my favorite Mushroom Swiss Burger. The process is pretty simple, but the caramelized onions do take some time. Feel free to omit them, or make them in advance so they’re ready to go whenever you’re craving a burger!
How to Make Caramelized Onions for Burgers
First up, onions! You’ll only need about 1 onion worth of caramelized onions for these burgers, but I always caramelize 3-4 at a time. You can store any leftovers in the fridge and use them on Meatball Subs or Red Wine Burgers.
- In a large stainless steel skillet, add a few Tablespoons of oil or butter (about 1 Tablespoon for each onion) along with a big ol’ pile of onions. Turn the heat to medium, cover, and cook, stirring regularly, until the onions are softened and starting to brown, about 7-9 minutes.
- Uncover, turn the heat to low, and continue to cook, stirring often, until the onions are very soft, sweet, and a deep brown color. If the onion starts to stick at any point, add a splash of water and scrape the bottom of the pan to deglaze. I usually have to do this 3-4 times throughout the process.
- You can remove the onions in as little as 30 minutes, or cook them for an hour or longer. They will continue to get softer and sweeter as you go. I take mine out around the 45 minute mark. Season with salt before serving.
Quick Pan Fried Mushrooms
I love using crimini mushrooms for this recipe, but white mushrooms work as well.
- Once the onions are done, remove them from the pan and deglaze again. Add a Tablespoon of butter to the skillet along with 8 ounces of sliced mushrooms.
- Let the mushrooms cook WITHOUT stirring, 4-5 minutes, or until golden brown on one side. Flip and continue to cook until browned on both sides. Add a minced garlic clove and saute for about a minute, then season to taste with salt.
For the Mushroom and Swiss Burger Patties:
I use my standard burger seasoning for this recipe, and form ¼-⅓ pound burgers.
Quick tips for super tender burgers:
- Handle the meat as little as possible.
- Gently form balls then press into patties.
- Leave an indent in the center to prevent an overly domed burger.
From there, you just have to cook! I’ve included instructions for cooking these burgers in a cast iron skillet, but you can also click here to learn how to grill burgers and here for air fryer hamburgers.
Whichever method you choose, add a slice (or two!) of Swiss cheese to your burger for the last 1-2 minutes of cook time.
Assembling your Epic Caramelized Onion, Mushroom and Swiss Burger
Now is the fun part. Assembly!
- First, let’s talk about buns. I LOVE a good brioche bun for burgers, but you also can’t go wrong with a sesame seed or onion roll. Choose whatever makes your heart go pitter patter.
- If you want to make your burger extra special, brush the buns with oil or melted butter and pop them in a skillet over medium heat (you can use the same one you used to cook the onions and mushrooms). They should be perfectly warm and toasty brown in 2-3 minutes.
- Now, add your cooked burgers (dripping with cheese) to the top of a bun slathered with mayo.
- Pile high with mushrooms and caramelized onions, then top with another bun, also slathered in mayo. I never skip the sauce, even for a burger with all these yummy toppings. It pulls everything together!
- Feel free to add greens (leaf lettuce, arugula, or spinach), or leave it plain.
More Burger Recipes You'll Love!
Or get your cheeseburger fix with this Crock Pot Cheeseburger Soup or Cheeseburger Tater Tot Casserole.
📖 Recipe
Mushroom Swiss Burger
Ingredients
For the onions:
- 3-4 sweet or yellow onions (thinly sliced)
- 3 Tablespoons butter (oil, or a blend of both)
- Water
- Kosher salt
For the mushrooms:
- 1 Tablespoon butter
- 8 ounces crimini mushrooms (sliced)
- 1 clove garlic (minced)
- Kosher salt and pepper (to taste)
For the burgers:
- 1 ½ pounds ground beef
- 1 teaspoon burger seasoning
- 5 thick slices Swiss cheese
- 5 brioche buns
- Lettuce or Arugula (optional)
- Mayonnaise (optional)
Instructions
For the onions:
- In a large stainless steel skillet, add the butter and the onions. Turn the heat to medium, cover, and cook, stirring regularly, until the onions are softened and starting to brown, about 7-9 minutes.
- Uncover, turn the heat to low, and continue to cook, stirring often, until the onions are very soft, sweet, and a deep brown color. If the onion starts to stick at any point, add a splash of water and scrape the bottom of the pan to deglaze. I usually have to do this 3-4 times throughout the process.
- You can remove the onions in as little as 30 minutes, or cook them for an hour or longer. They will continue to get softer and sweeter as you go. I take mine out around the 45 minute mark. Season to taste with salt.
For the mushrooms:
- Deglaze the onion pan. Melt the butter in the skillet and add the mushrooms.
- Let them cook WITHOUT stirring, 4-5 minutes, or until golden brown on one side. Flip and continue to cook until browned on both sides. Add the garlic and saute for about a minute, then season to taste with salt.
For the burgers:
- Gently shape the beef into five equal sized balls then use the palm of your hand to press them into a flat patty shape. It’s okay if the edges aren’t perfectly round. Use your thumb to press an indent into the center of each patty, then sprinkle both sides with burger seasoning.
- Heat a cast iron skillet over medium high heat. Add the patties and cook until browned on the bottom, about 4-5 minutes. Flip over, and cook an additional 3-4 minutes or until it reaches an internal temperature of 165 degrees. Add the cheese for the last 2 minutes of cooking.
- To assemble, spread the mayonnaise on the buns (if using). Top each one with a burger patty, caramelized onions, and mushrooms. Add greens if desired. Serve.
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