Mushroom Swiss Burger Caramelized Onions (Printer-friendly)
Juicy beef patty topped with sautéed mushrooms, sweet onions, and melted Swiss cheese.
# What you'll need:
→ Caramelized Onions
01 - 2 large yellow onions, thinly sliced
02 - 2 tbsp unsalted butter
03 - 1 tbsp olive oil
04 - 1/2 tsp salt
05 - 1 tsp sugar (optional)
→ Mushrooms
06 - 9 oz cremini or button mushrooms, sliced
07 - 1 tbsp unsalted butter
08 - 1 tbsp olive oil
09 - 1/4 tsp freshly ground black pepper
10 - 1/4 tsp salt
11 - 1 tsp fresh thyme leaves
→ Burgers
12 - 1.3 lbs ground beef (80/20 blend recommended)
13 - 1 tsp salt
14 - 1/2 tsp black pepper
15 - 4 slices Swiss cheese
16 - 4 brioche or hamburger buns
17 - 1 tbsp unsalted butter (for toasting buns)
→ Toppings & Condiments
18 - 4 leaves lettuce
19 - 4 tomato slices
20 - 2 tbsp mayonnaise
21 - 1 tbsp Dijon mustard
# Method:
01 - In a large skillet over medium-low heat, melt butter and olive oil. Add sliced onions and salt. Cook, stirring occasionally, for 20-25 minutes until deep golden brown and soft. Add sugar if desired for extra sweetness. Remove from pan and set aside.
02 - In the same skillet, heat butter and olive oil over medium heat. Add mushrooms, salt, pepper, and thyme. Cook for 6-8 minutes until mushrooms are browned and tender. Set aside.
03 - Divide ground beef into 4 equal portions and shape into patties slightly larger than your buns. Season both sides with salt and pepper.
04 - Preheat a grill or skillet over medium-high heat. Cook patties for 3-4 minutes per side for medium doneness, or until desired doneness is reached. In the last minute of cooking, place a slice of Swiss cheese on each patty, cover, and let melt.
05 - Spread butter on the cut sides of each bun. Toast on the grill or in a pan until golden brown.
06 - Spread mayonnaise and Dijon mustard on the bottom bun. Add lettuce and tomato. Place the burger patty with melted Swiss cheese on top, then add a generous spoonful of sautéed mushrooms and caramelized onions. Cap with the top bun and serve immediately.
# Expert Tips:
01 -
- The caramelized onions smell so good while cooking that your whole kitchen becomes part of the promise.
- Swiss cheese melts in a way that feels almost creamy, and the mushrooms add an umami depth that makes this feel restaurant-quality without the pretense.
- It comes together in under an hour, which means you can actually pull this off on a weeknight without stress.
- The combination of tender, sweet, and savory hits so many notes that it feels indulgent but stays balanced.
02 -
- Don't skip the low heat for the onions—high heat will burn them before they caramelize, and you'll end up with bitter onions instead of sweet ones.
- Resist the urge to add sugar to the onions unless they really won't caramelize after 20 minutes; good onions don't need it, and sugar can sometimes turn them burnt-tasting instead of sweet.
- Handle the beef as little as possible when forming patties; overworking it makes tough burgers instead of tender ones.
- Let the cooked burgers rest for a minute before assembling so the cheese sets and the juices redistribute instead of running all over the plate.
03 -
- Form your patties and season them right before cooking; if you do it too early, the salt starts to break down the proteins and makes them dense instead of tender.
- The indent in the center of each patty isn't just for looks—it keeps the burger from puffing up in the middle and cooking unevenly, so you get that nice flat surface for the cheese to melt across.