Mushroom Swiss Burger Caramelized Onions (Printable)
Juicy beef patty layered with Swiss cheese, sautéed mushrooms, and caramelized onions 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 - 1/2 tsp sugar
06 - 1 tbsp balsamic vinegar (optional)
→ Sautéed Mushrooms
07 - 9 oz cremini or button mushrooms, sliced
08 - 1 tbsp unsalted butter
09 - 1 tbsp olive oil
10 - 1 clove garlic, minced
11 - Salt and pepper, to taste
→ Beef Patties and Assembly
12 - 1.3 lbs ground beef (80/20 blend)
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, softened (for toasting buns)
→ Optional Toppings
18 - Fresh lettuce leaves
19 - Sliced tomatoes
20 - Dijon mustard or mayonnaise
# How To Cook:
01 - In a large skillet, melt butter with olive oil over medium heat. Add sliced onions, salt, and sugar. Cook, stirring frequently, until onions are golden brown and soft, approximately 20 minutes. Stir in balsamic vinegar during the last 2 minutes, if using. Remove from heat and set aside.
02 - Heat butter and olive oil in a medium skillet over medium-high heat. Add mushrooms and cook until browned and tender, about 7 minutes. Incorporate minced garlic, season with salt and pepper, and cook for an additional minute. Set aside.
03 - Form ground beef into 4 equal patties approximately 3/4 inch thick. Season both sides with salt and black pepper.
04 - Preheat grill or skillet over medium-high heat. Cook patties for 3 to 4 minutes per side for medium doneness or until desired. During the last minute, place a slice of Swiss cheese on each patty and cover to melt.
05 - Spread softened butter on the cut sides of buns. Toast them cut side down on the skillet or grill until golden brown.
06 - Layer lettuce and tomato on the bottom bun if using. Add the cheese-topped patty, then top with sautéed mushrooms and caramelized onions. Spread Dijon mustard or mayonnaise on the top bun if desired. Close and serve warm.
# Expert Tips:
01 -
- The caramelized onions transform from sharp to honey-sweet over 20 minutes, adding depth that elevates everything else on the burger.
- Cooking each topping separately means nothing gets overlooked or soggy, and you control the texture of every layer.
- It's gourmet enough to impress, but the actual technique is just patience and good timing.
02 -
- Don't press the burgers while they cook; it squeezes out the juice and makes them tough and dry.
- Keep the onions and mushrooms on their own journey; they need time to develop flavor and shouldn't be rushed or mixed with the burger cooking.
- Cold beef patties cook more evenly, so shape them a few minutes before cooking if you have time.
03 -
- Add a splash of Worcestershire sauce to the sautéing mushrooms for an umami punch that makes people ask what your secret ingredient is.
- Toast your buns on the grill grates rather than a flat surface; the lines add texture and keep them from getting too soft.