Pan-Seared Mushroom Swiss Burgers

Name: Pan-Seared Mushroom Swiss Burgers
Prep time: 20 min
Cook time: 30 min
Total time: 50 min
Yield: 4 servings
Cuisine: American
Ingredients: 12 oz (340 g) cremini mushrooms, wiped clean, stems trimmed, sliced ¼-inch (6 mm) thick; 1 large (about 8 oz) (225 g) large yellow onion, halved and thinly sliced into half-moons; 2 tbsp (28 g) unsalted butter, divided into two 1-tbsp portions; 1 tbsp (15 ml) olive oil; 2 cloves (6 g) garlic cloves, minced; 1 tsp (2 g) fresh thyme leaves, stripped from the stems; 2 tsp (10 ml) Worcestershire sauce; 1½ lb (680 g) 80/20 ground beef, cold, divided into four 6-oz (170 g) portions; 1½ tsp (9 g) kosher salt, ½ tsp for the topping and 1 tsp for the patties; ¾ tsp (2 g) freshly ground black pepper, ¼ tsp for the topping and ½ tsp for the patties; 4 slices (about 4 oz) (113 g) Swiss cheese slices, at room temperature; 4 buns (280 g) burger buns, split; 1 tbsp (14 g) unsalted butter, softened; 4 tbsp (60 g) mayonnaise; 1 tbsp (15 g) Dijon mustard

From the MyKitchenBank Kitchen

Juicy skillet-seared beef patties piled with deeply browned cremini mushrooms and soft sweet onions, then blanketed in melted Swiss and tucked into buttery toasted buns with a tangy Dijon mayo.

Prep: 20 min
Cook: 30 min
Wait: 3 min
Total: 53 min
Makes: 4 burgers

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Ingredients

4 servings

For the mushroom-onion topping
12 oz (340 g) cremini mushrooms, wiped clean, stems trimmed, sliced ¼-inch (6 mm) thick
1 large (about 8 oz) (225 g) large yellow onion, halved and thinly sliced into half-moons
2 tbsp (28 g) unsalted butter, divided into two 1-tbsp portions
1 tbsp (15 ml) olive oil
2 cloves (6 g) garlic cloves, minced
1 tsp (2 g) fresh thyme leaves, stripped from the stems
2 tsp (10 ml) Worcestershire sauce
For the burgers
1½ lb (680 g) 80/20 ground beef, cold, divided into four 6-oz (170 g) portions
1½ tsp (9 g) kosher salt, ½ tsp for the topping and 1 tsp for the patties
¾ tsp (2 g) freshly ground black pepper, ¼ tsp for the topping and ½ tsp for the patties
4 slices (about 4 oz) (113 g) Swiss cheese slices, at room temperature
To assemble
4 buns (280 g) burger buns, split
1 tbsp (14 g) unsalted butter, softened
4 tbsp (60 g) mayonnaise
1 tbsp (15 g) Dijon mustard

Equipment (5)

12-inch (30 cm) heavy skillet, cast iron or stainless steel, with a lid or large baking sheet to use as a cover
Medium bowl for the cooked topping
Wide metal spatula
Instant-read thermometer
Cutting board and sharp knife

Steps

Before you start

Keep the ground beef refrigerated until you shape the patties; cold meat stays juicier and holds together better.
Slice the Swiss cheese or take it out of the fridge 15 minutes ahead so it melts quickly and evenly.
You will cook the topping first and the burgers second in the same skillet, so have a bowl ready to hold the mushrooms and onions.
Turn on your exhaust fan; searing beef over medium-high heat makes some smoke.

1
Prep the topping
- Slice the mushrooms ¼ inch (6 mm) thick, slice the onion into thin half-moons, mince the garlic, and strip the thyme leaves.
- In a small bowl, stir the mayonnaise and Dijon mustard together and refrigerate until serving.
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Ready when: Mushroom slices are all roughly the same thickness so they brown evenly.
Tip: Wipe mushrooms with a damp towel instead of rinsing them; water makes them steam instead of brown.
2
Shape the patties
- Divide the beef into four 6-oz (170 g) portions.
- Gently form each into a ¾-inch (2 cm) thick patty about 4½ inches (11 cm) wide, handling the meat as little as possible.
- Press a shallow dimple into the center of each patty with your thumb.
- Refrigerate on a plate while you cook the topping.
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Ready when: Patties hold together with no cracks around the edges.
Tip: Do not salt the beef yet; salt too early makes the texture dense and sausage-like.
3
Brown the mushrooms
- Heat the 12-inch skillet over medium-high heat for 1 minute.
- Add the olive oil and 1 tbsp of the topping butter.
- When the butter foams, add the mushrooms in a mostly single layer.
- Cook without stirring for 3 minutes, then stir and cook 4 to 5 minutes more.
- Sprinkle with ½ tsp of the salt and ¼ tsp of the pepper.
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Ready when: Mushrooms have released their liquid, the pan looks dry again, and the slices are deep golden brown.
Tip: If your skillet is smaller than 12 inches, brown the mushrooms in two batches so they don't steam.
4
Soften the onions
- Reduce the heat to medium.
- Add the remaining 1 tbsp topping butter and the onions to the mushrooms.
- Cook, stirring every minute or so and scraping up the browned bits, for 8 to 10 minutes.
- Stir in the garlic and thyme and cook 30 seconds, then add the Worcestershire sauce and stir for 15 seconds until it evaporates.
- Scrape everything into a bowl and cover loosely to keep warm.
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Ready when: Onions are soft, golden, and slightly sweet-smelling; garlic smells fragrant but is not dark brown.
Tip: If the browned bits on the pan start to scorch, lower the heat to medium-low.
5
Sear the burgers
- Wipe the skillet with a paper towel, leaving a thin film of fat, and return it to medium-high heat for 2 minutes.
- Season both sides of the patties with the remaining 1 tsp salt and ½ tsp pepper.
- Place the patties in the hot skillet and cook undisturbed for 4 minutes until a dark brown crust forms.
- Flip and cook 3 minutes more for medium-well.
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Ready when: Deep brown crust on both sides and an instant-read thermometer inserted sideways into the center reads 160°F (71°C).
Tip: Never press down on the patties with the spatula; it squeezes out the juices.
6
Melt the cheese
- Pile a quarter of the mushroom-onion mixture on each patty, then lay a slice of Swiss over each pile.
- Cover the skillet with the lid or a baking sheet and cook 1 minute over medium-high heat.
- Move the burgers to a plate.
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Ready when: Cheese is fully melted and drooping over the mushrooms.
Tip: If the cheese isn't melted after 1 minute, add 1 tsp water to the pan edge before covering again; the steam helps.
7
Toast the buns
- Spread the softened butter on the cut sides of the buns.
- Place them cut-side down in the same skillet over medium heat and toast for 1 to 2 minutes, using the leftover beef fat for extra flavor.
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Ready when: Cut sides are golden brown and slightly crisp.
Tip: Watch closely; buttered buns go from golden to burnt in seconds.
8
Rest and assemble
- Let the topped burgers rest for 3 minutes so the juices settle.
- Spread the Dijon mayo on the toasted buns, set each burger on a bottom bun, add the top bun, and serve right away.
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Ready when: Burgers are hot, juicy, and the cheese is still soft.

Good to know

Tips

Use 80/20 beef; leaner beef turns dry in a pan-seared burger.
Let the mushrooms sit undisturbed for the first 3 minutes so they brown rather than steam.
Cook the burgers in the same skillet as the topping to pick up the browned bits and extra flavor.
For medium-well burgers, use the 160°F (71°C) reading; the patties will keep rising a few degrees as they rest.

Make ahead

"Cook the mushroom-onion topping up to 3 days ahead and refrigerate in an airtight container; reheat in the skillet over medium heat for 2 minutes. Shape the patties up to 1 day ahead, cover, and refrigerate, and mix the Dijon mayo up to 3 days ahead."

Storage & reheating

"Room temperature: no more than 2 hours. Fridge: store leftover patties and topping separately in airtight containers for up to 3 days. Freezer: freeze cooked patties up to 2 months. Reheat patties in a covered skillet over medium-low heat for 4 to 5 minutes (to 165°F/74°C), or microwave in 30-second bursts, then top with warmed mushrooms, fresh Swiss, and a toasted bun."

Substitutions

Swiss cheese slices → Gruyère or provolone. Gruyère is nuttier and melts beautifully; provolone is milder.
cremini mushrooms → white button or baby bella mushrooms. Same weight and cooking time; button mushrooms have a milder flavor.
fresh thyme leaves → ¼ tsp dried thyme. Add it with the garlic.
burger buns → brioche buns or ciabatta rolls. Brioche browns faster, so toast about 1 minute.