Beef and Mushroom Blended Burgers with Thyme

Name: Beef and Mushroom Blended Burgers with Thyme
Prep time: 22 min
Cook time: 21 min
Total time: 43 min
Yield: 4 servings
Cuisine: American
Ingredients: 10 oz (285 g) cremini mushrooms, wiped clean, stems trimmed, very finely chopped into pieces about ⅛ inch (3 mm); 1 tbsp (15 ml) olive oil; 2 cloves (8 g) garlic, finely minced; 2 tsp (4 g) fresh thyme leaves, stripped from the stems; 1 tsp (5 ml) soy sauce; 1 lb (454 g) 80/20 ground beef, cold, straight from the fridge; ¾ tsp (4½ g) fine sea salt; ½ tsp (1 g) black pepper, freshly ground; 1 tsp (5 ml) avocado or canola oil, for the searing pan; 4 tbsp (56 g) mayonnaise; 2 tsp (10 g) Dijon mustard; 4 buns (260 g) whole grain burger buns, split; 4 slices (90 g) Swiss or Gruyère cheese slices (optional); 1 medium (150 g) ripe tomato, cut into 4 slices about ¼ inch (6 mm) thick; 1 cup (20 g) baby arugula, loosely packed

From the MyKitchenBank Kitchen

Finely chopped cremini mushrooms are browned with garlic and thyme, then folded into ground beef for juicy, deeply savory burgers with less beef and more flavor. A hard pan-sear gives a crisp crust, and a toasted whole grain bun with Dijon mayo finishes them.

Prep: 22 min
Cook: 21 min
Wait: 28 min
Total: 1 hr 11 min
Makes: 4 burgers

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Ingredients

4 servings

For the patties
10 oz (285 g) cremini mushrooms, wiped clean, stems trimmed, very finely chopped into pieces about ⅛ inch (3 mm)
1 tbsp (15 ml) olive oil
2 cloves (8 g) garlic, finely minced
2 tsp (4 g) fresh thyme leaves, stripped from the stems
1 tsp (5 ml) soy sauce
1 lb (454 g) 80/20 ground beef, cold, straight from the fridge
¾ tsp (4.5 g) fine sea salt
½ tsp (1 g) black pepper, freshly ground
1 tsp (5 ml) avocado or canola oil, for the searing pan
For the Dijon mayo
4 tbsp (56 g) mayonnaise
2 tsp (10 g) Dijon mustard
To serve
4 buns (260 g) whole grain burger buns, split
4 slices (90 g) Swiss or Gruyère cheese slices (optional)
1 medium (150 g) ripe tomato, cut into 4 slices about ¼ inch (6 mm) thick
1 cup (20 g) baby arugula, loosely packed

Equipment (8)

12-inch (30 cm) cast-iron or heavy stainless skillet, with a lid that fits
Large nonstick or stainless skillet, 10–12 inch (25–30 cm), for the mushrooms (or use the same skillet, wiped out)
Sharp knife and cutting board, or a food processor
Large mixing bowl
Rimmed plate for cooling mushrooms, plus a plate or tray lined with parchment paper for chilling patties
Wide metal spatula
Instant-read thermometer
Small bowl for the sauce

Steps

Before you start

Keep the ground beef in the fridge until the moment you mix; cold fat gives juicier burgers.
Cooked mushrooms must cool to room temperature before mixing, or they will melt the beef fat. Plan for about 15 minutes.
Use 80/20 ground beef. Leaner beef will make the blended patties dry.
Turn on your exhaust fan and open a window; high-heat searing makes smoke.
Have an instant-read thermometer ready. Ground beef burgers must reach a safe internal temperature of 160°F (71°C). No oven is needed; everything is cooked on the stovetop.

1
Chop the mushrooms
- Wipe the cremini caps with a damp paper towel and trim the stem ends.
- Chop very finely into pieces about ⅛ inch (3 mm), or pulse in a food processor in 1-second bursts, 6–8 times, scraping down once.
- You want a coarse crumble, not a paste.
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Ready when: Mushroom pieces are uniformly small and still look distinct, like coarse crumbs.
Tip: Don't wash mushrooms under running water; they soak it up and take much longer to brown.
2
Brown the mushrooms
- Heat the olive oil in a large skillet over medium-high heat until it shimmers.
- Add the mushrooms in an even layer and cook, stirring every 30–60 seconds, for 8–9 minutes.
- They will first release liquid, then the pan will turn dry and the mushrooms will start to brown.
- Reduce to medium, add the garlic, thyme and soy sauce, and stir for 1 minute until fragrant.
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Ready when: All liquid has evaporated, mushrooms are deep golden-brown and reduced to roughly 1 cup (about 120 g), and the garlic smells toasty, not burnt.
Tip: If the pan still looks wet, keep cooking. Leftover moisture makes soft, crumbly patties.
3
Cool the mushrooms
- Scrape the mushroom mixture onto a plate and spread it thin.
- Let it cool until no longer warm to the touch.
- Transfer the plate to the fridge to speed this up if you like.
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Ready when: Mushrooms feel cool or room temperature when touched.
Tip: Use this time to make the sauce and slice the tomato.
4
Make sauce and prep toppings
- Stir the mayonnaise and Dijon together in a small bowl.
- Slice the tomato into 4 rounds about ¼ inch (6 mm) thick and measure out the arugula.
- Set the buns, cheese, tomato and arugula near the stove.
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Ready when: Sauce is smooth and evenly pale tan.
5
Mix and shape patties
- Put the cold ground beef in a large bowl.
- Add the cooled mushrooms, salt and pepper.
- Mix with your hands for about 20–30 seconds, only until the mushrooms are evenly distributed.
- Divide into 4 portions of about 5 oz (140 g) each.
- Gently shape each into a patty about 4 inches (10 cm) wide and ¾ inch (2 cm) thick, then press a shallow dimple, about ¼ inch (6 mm) deep, in the center of each with your thumb.
- Wash your hands with soap and hot water after handling the raw beef.
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Ready when: Mushroom is evenly speckled through the beef and patties hold together when lifted.
Tip: Overmixing makes tough, dense burgers. Handle the meat as little as possible.
6
Chill the patties
- Place the patties on a plate or tray lined with parchment and refrigerate, uncovered, for 10 minutes so they firm up and keep their shape in the pan.
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Ready when: Patties feel firm and cold to the touch.
7
Sear the burgers
- Heat a 12-inch (30 cm) cast-iron skillet over medium-high heat for 3 minutes, then add the avocado or canola oil and swirl.
- Season both sides of each patty lightly with a pinch of extra salt if desired.
- Add the patties and cook without moving for 4 minutes until a deep brown crust forms.
- Flip once and cook 3–4 minutes more.
- Check the internal temperature: the ground beef must reach 160°F (71°C) in the center.
- If using cheese, lay a slice on each patty in the last minute, cover the pan with a lid, and cook until melted.
- If any patty is below 160°F (71°C), keep cooking and re-check every minute.
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Ready when: Deep brown crust on both sides, no pink in the center, and an instant-read thermometer inserted sideways into the center of each patty reads at least 160°F (71°C).
Tip: Don't press down on the patties with the spatula; it squeezes out the juices.
8
Toast the buns
- Transfer the burgers to a plate.
- Reduce heat to medium, place the split buns cut-side down in the beef-and-mushroom drippings, and toast for 1–2 minutes.
- If the pan looks dry, tilt it so any remaining drippings coat the buns.
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Ready when: Cut sides are golden-brown and lightly crisp.
Tip: Watch closely; whole grain buns go from toasted to burnt quickly.
9
Rest and assemble
- Let the burgers rest on the plate for 3 minutes so the juices settle.
- Spread the Dijon mayo on both halves of each bun.
- Layer the bottom bun with arugula, a tomato slice, and the burger, then cover with the top bun.
- Serve right away.
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Ready when: Burgers are still hot but no longer sizzling, and the tops of the buns sit level.
Tip: Put the arugula under the patty so the heat doesn't wilt it too quickly.

Good to know

Tips

Brown the mushrooms until the pan is truly dry; moisture is the main cause of soft, crumbly blended burgers.
Keep everything cold: cooled mushrooms, cold beef, and a 10-minute chill give a better crust and juicier center.
Make the dimple in the center of each patty so it cooks flat instead of puffing into a dome.
Use a thermometer. Mushrooms keep the patties moist and brown, so color alone is unreliable; always confirm 160°F (71°C).

Make ahead

Cook and cool the mushrooms up to 2 days ahead and refrigerate in an airtight container. Shaped raw patties can be refrigerated, covered, for up to 24 hours; separate with parchment. Mix the Dijon mayo up to 3 days ahead.

Storage & reheating

Room temperature: no more than 2 hours. Fridge: store cooked patties (without buns or toppings) in an airtight container for up to 3 days. Freezer: freeze raw patties separated by parchment for up to 3 months, or cooked patties for up to 2 months; thaw raw patties overnight in the fridge before cooking. Reheat cooked patties in a covered skillet over medium-low heat for 4–5 minutes per side, or until they reach 165°F (74°C) in the center.

Substitutions

cremini mushrooms → white button or baby bella mushrooms. Same weight, same method. Button mushrooms are milder in flavor.
fresh thyme leaves → 1 tsp dried thyme. Add it with the garlic and stir for 30 seconds to wake it up.
Swiss or Gruyère cheese slices → sharp cheddar or provolone. Melts the same way; use the same one slice per burger.
soy sauce → Worcestershire sauce. Use 1 tsp. Not gluten-free or vegetarian; use tamari if you need gluten-free.