Mushroom Swiss Burger Onions (Print Version)
Juicy burger with earthy mushrooms, sweet caramelized onions, and melted Swiss cheese on a toasted bun.
# What You 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)
→ Sautéed 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 (optional)
→ 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 (optional)
21 - 1 tbsp Dijon mustard (optional)
# How to Make It:
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 heat and set aside.
02 - Using the same skillet, heat butter and olive oil over medium heat. Add mushrooms, salt, pepper, and thyme if using. Cook 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 the buns. Season both sides with salt and black pepper.
04 - Preheat grill or skillet over medium-high heat. Cook patties for 3-4 minutes per side for medium doneness or until desired doneness is reached. Place Swiss cheese slices on patties during the last minute of cooking and cover to melt.
05 - Spread butter on cut sides of each bun. Toast on grill or in a pan until golden brown.
06 - Spread mayonnaise and Dijon mustard (if using) on bottom buns. Layer with lettuce and tomato slices. Top with cheese-melted patties, then add sautéed mushrooms and caramelized onions. Cap with top buns and serve immediately.
# Expert Hints:
01 -
- The caramelized onions taste like you spent hours on them, but they only ask for 20 minutes of occasional stirring.
- Swiss cheese melts into those mushrooms in a way that feels almost decadent for a weeknight burger.
- There's a quiet satisfaction in serving something that looks restaurant-worthy from your own kitchen.
02 -
- Caramelization takes real time—rushing it with high heat gives you burned onions, not caramel, and they taste bitter instead of sweet.
- Don't form your burger patties more than an hour ahead; ground beef gets dense and tough if the patties sit too long before cooking.
- Toast your buns without fail; it's the difference between a burger that holds together and one that falls apart in your hands.
03 -
- A splash of Worcestershire sauce stirred into the mushrooms in the final minute deepens their flavor without making them taste like anything other than themselves.
- If you're cooking these for a crowd, make your patties and caramelize your onions ahead, then finish everything just before serving—the timing becomes almost effortless.