Mushroom Swiss Burger Recipe

Form and season patties

Divide the ground beef into one 10 oz. patty (approximately 283 g). Handle gently and form into a round patty about 3/4 to 1 inch thick with a slight dimple in the center to prevent doming. Season both sides evenly with 1 tsp kosher salt and 1/2 tsp freshly ground black pepper. Brush or rub 1 tbs Worcestershire sauce onto both sides.

Cook patties

Heat a heavy skillet or cast-iron pan over medium-high heat until very hot. Add 1 tsp neutral oil and swirl to coat. Place the patty in the pan and sear without moving for 3-4 minutes until a deep brown crust forms. Flip and cook 3-4 more minutes for medium (adjust time for desired doneness). In the last 1-2 minutes of cooking, reduce heat to medium, top the patty with the Swiss cheese (3 oz total) to melt, and cover the pan briefly (30–60 seconds) to help cheese melt. Remove patty to a plate and tent loosely with foil to rest for 5 minutes.

Slice onions

Peel and slice the large yellow onion in half pole-to-pole, then thinly slice into half-moons (about 1/8-inch thick).

Caramelize

In a separate large skillet, heat 1 tbsp unsalted butter and 1 tsp olive oil over medium-low heat. Add the sliced onions and 1/2 tsp kosher salt; stir to coat. Cook slowly, stirring every 3–5 minutes, for 20–30 minutes until onions are deeply golden and soft. If they cling to the pan or need help browning, raise heat to medium briefly, stirring, then return to medium-low. If desired to speed the process slightly, sprinkle 1/4 tsp sugar after 10 minutes. Stir in 1 tsp balsamic vinegar at the end for a touch of acidity. Keep warm until assembly.

Prepare mushrooms

Wipe mushrooms clean with a damp cloth and slice into 1/4-inch thick slices. Mince 1 clove garlic and measure thyme.

Sauté

Heat 1 tbsp butter and 1 tsp olive oil in a skillet over medium-high heat until shimmering. Add the sliced mushrooms in a single layer (work in batches if needed). Let them cook undisturbed for 2–3 minutes to develop color, then stir and continue cooking until golden and reduced, about 4–6 minutes total. Add minced garlic, 1/2 tsp kosher salt, 1/4 tsp pepper, and thyme; cook 30–60 seconds until fragrant. Remove from heat and keep warm.

Toast buns

Butter the cut faces of the 2 burger buns with 1 tsp softened butter. Toast them face-down in a clean skillet over medium heat until golden, about 1–2 minutes. Remove and set aside.

Assemble the burger

Place the rested, cheese-melted patty on the bottom bun. Spoon a generous portion of the sautéed mushrooms over the cheese, then pile on the caramelized onions. Add optional condiments (mayonnaise, mustard, aioli) and lettuce or pickles if using. Top with the bun crown and press lightly.

Serve

Slice in half if desired and serve immediately while hot. Recommended sides: fries, chips, or a simple salad.