This is a copycat of Shake Shack’s ‘Shroom Burger — a large portobello cap stuffed with a cheddar-Muenster blend, breaded in panko, and shallow-fried until golden. The honest reason to make it at home: it’s cheaper than the original, you control the oil temperature, and the molten cheese center is genuinely impressive for how straightforward the process is.
What makes this version work
Two things actually matter here. First, freezing the cheese mounds before stuffing — this keeps the filling solid long enough to survive the dredging and frying process without leaking out before the crust sets. Skip this step and you’ll lose most of the cheese to the oil. Second, oil temperature control during frying is the difference between a crispy, evenly browned crust and a greasy, pale one. Too cool and the panko absorbs oil; too hot and the outside burns before the cheese melts. A steady 350°F (175°C) is the target — use a thermometer if you have one, or test with a pinch of breadcrumbs: they should sizzle immediately and turn golden within 30 seconds.
Troubleshooting
- The breading falls off during frying: The mushroom cap is releasing moisture and breaking the coating’s grip. After cleaning and de-gilling, pat the caps completely dry with paper towels and let them sit uncovered on a rack for 10 minutes before dredging. Any surface moisture will cause the flour layer to slide.
- The crust is soggy, not crispy: You likely overcrowded the pan, which drops the oil temperature fast. Fry one mushroom at a time if your pan is small. Also, drain on a wire rack, not paper towels — paper traps steam underneath and softens the crust.
- The cheese didn’t melt inside: The frozen cheese mounds were too large or the frying time was too short. Keep each mound to about a tablespoon and make sure the mushroom fries for the full time on each side. If the crust is browning too fast, lower the heat slightly rather than pulling the mushroom early.
- The mushroom tastes watery or bitter: Gills were left in. Remove them with a spoon before stuffing — they hold moisture and can give an off flavor once fried.
- The bun goes soggy before you finish eating: Spread the mayo-mustard sauce on both cut sides of the toasted bun, then add the lettuce directly on top of the sauce. The lettuce acts as a moisture barrier between the sauce and the hot fried patty.
Storage and reheating
Store leftover fried mushroom patties on their own — not assembled — in an airtight container in the fridge for up to 2 days. To reheat, use an oven or air fryer at 375°F (190°C) for 8–10 minutes; this brings the crust back to something close to crispy and re-melts the cheese. A microwave will make the breading soft and the mushroom rubbery, so skip it. Freezing a fully fried patty is not recommended — the breading turns mushy on thawing. If you want to prep ahead, freeze the stuffed, unbattered mushrooms instead, then dredge and fry straight from frozen, adding 2–3 extra minutes of fry time.
Crispy Shake Shack-Style Mushroom Burger
Ingredients
Mushroom Patties
- 4 large portobello mushroom caps stems and gills removed, cleaned and dried
- ½ cup shredded cheddar cheese preferably sharp
- ½ cup shredded Muenster cheese
- 1 cup all purpose flour
- 2 large eggs beaten
- 1.5 cups panko breadcrumbs preferably Japanese style for extra crispness
- 2.5 cups vegetable oil for frying, or enough to cover patties half-way
Burger Assembly
- 4 medium potato buns split and toasted
- ¼ cup mayonnaise
- 1 tablespoon Dijon mustard
- 4 leaves butter lettuce or romaine hearts
- 4 slices ripe tomato beefsteak preferably, 1 per burger
- ¼ teaspoon kosher salt
- ¼ teaspoon freshly cracked black pepper
Instructions
- Make Cheese Filling: Mix shredded cheddar and Muenster cheeses in a bowl. Form small mounds (about 2 tablespoons each). Place mounds onto a parchment-lined tray and freeze for 10 minutes until firm.
- Stuff Mushrooms: Sandwich a mound of cheese between two mushroom caps, pressing gently to seal. Repeat for remaining caps.
- Bread the Mushrooms: Set up a dredging station with flour, beaten eggs, and panko in separate bowls. Dredge each stuffed mushroom in flour (shake off excess), then dip in egg, then coat thoroughly in panko. Lightly press so crumbs adhere well.
- Fry: Heat vegetable oil in a heavy skillet or Dutch oven over medium-high heat (350°F / 175°C). Carefully fry each patty for 3–4 minutes per side, until golden brown and crisp. Drain on paper towels.
- Prepare Sauce: In a small bowl, mix mayonnaise and Dijon mustard. Set aside.
- Toast Buns: Lightly butter and toast potato buns on a grill pan or skillet until golden, 1–2 minutes.
- Assemble: Spread mayo-mustard sauce on each bun base. Add lettuce, a tomato slice, and the crispy mushroom patty. Sprinkle with salt and pepper. Top with the bun lid and serve immediately.
Notes
- For a vegan version, use dairy-free cheese and egg replacer, and choose vegan buns.
- For extra crispness, double-coat the patties by repeating the egg and panko steps.
- You can assemble the cheese-stuffed mushrooms a day ahead and refrigerate until ready to fry.
Nutrition
Frequently asked questions
Can I use smaller mushrooms instead of large portobello caps?
Smaller mushrooms won’t work well here — you need a cap large enough to hold a meaningful amount of cheese and still close around it. Standard portobello caps (around 4–5 inches across) are the minimum; anything smaller makes stuffing nearly impossible and the cheese-to-mushroom ratio suffers.
What if I can’t find Muenster cheese?
Low-moisture mozzarella is the best substitute — it melts smoothly and doesn’t release much liquid during frying. Provolone also works. Avoid fresh mozzarella, which has too much water content and can make the stuffing wet.
How do I know the mushroom is cooked through without cutting it open?
Fry for the full time specified in the recipe card and the mushroom will be done — portobello caps cook quickly once the oil is at temperature. If you press the top of the cap gently with tongs and it gives slightly (rather than feeling firm and raw), it’s ready; the cheese inside will also feel soft through the crust.
If you liked this one
- Five Guys Veggie Sandwich copycat
- Veggie Whopper copycat recipe
- Mushroom Swiss King copycat
- Halloumi King Burger homage