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portobello mushroom sandwich with toppings on a bun

Portobello Mushroom Sandwich

  • Author: Katie Webster
  • Total Time: 30 mins
  • Yield: 4 Sandwiches 1x
  • Diet: Vegetarian


These 30-minute portobello mushroom sandwiches are simple to make, juicy and delicious. They are made with succulent roasted portobello caps, and traditional burger toppings like lettuce, tomato, onion and pickles. Everyone will love this Portobello Mushroom Burger Sandwich!



For The Mushrooms:

4 large portobello mushrooms, stems removed and gills scraped out

1 tablespoon extra-virgin olive oil

1 tablespoon soy sauce or tamari

Freshly ground pepper, to taste

For The Sandwiches:

4 kaiser rolls or sandwich rolls, split and toasted

8 tablespoons Burger Sauce or Special Sauce, see ingredient note

4 leaves green leaf lettuce or 1 1/2 cup arugula

1 medium tomato, cored sliced

2 slices red onion, broken into rings

12 dill pickle chips


  1. Prepare Mushrooms: Preheat oven to 400 degrees F. Brush insides and outsides of mushrooms with oil and soy sauce. Season with pepper. Arrange mushrooms, gill side up, on a baking sheet.
  2. Roast the mushrooms until tender and beginning to brown, about 15 minutes. Flip mushrooms, discard any accumulated juices, and roast until mushrooms are brown and slightly dry, about 5 minutes more.
  3. Meanwhile, lay rolls, cut side up on work surface. Spread burger sauce over the buns, dividing evenly. Place the lettuce on the bottom bun. 
  4. Top the lettuce with the portobello. Top with tomato, onion and pickle chips, dividing evenly. Top each sandwich with the roll tops and serve immediately.


Ingredient Note: We like Sir Kensington Special Sauce for these sandwiches. There are other burger sauces on the market including large national brands like Hellmans and Heinz. Find them in the condiment section near the mayonnaise. You can also make your own using ¼ cup mayonnaise, 2 tablespoons ketchup, 1 teaspoon yellow mustard, 1 teaspoon relish, 1 teaspoon lemon juice or white vinegar, 1/8 teaspoon garlic powder, and a pinch each celery salt and pepper. Whisk it well and use in place of the store-bought sauce.  

Tip: To Make this recipe vegan, substitute Vegan Burger Sauce or  Vegan Mayonnaise for the burger sauce.

Make Ahead: Portobellos can be roasted up to three days ahead. Re-warm in the microwave for 30 seconds per cap, or until steaming hot before assembling sandwiches.

  • Prep Time: 5 mins
  • Active Time: 15 mins
  • Cook Time: 20 mins
  • Category: Main Course
  • Method: Oven
  • Cuisine: American


  • Serving Size: 1 Sandwich
  • Calories: 395 cals
  • Sugar: 4 g
  • Fat: 19 g
  • Carbohydrates: 46 g
  • Fiber: 4 g
  • Protein: 10 g

Keywords: Portobello Mushroom Sandwich, Portobello Mushroom Sandwiches, Portobello Mushroom Burger, Portobello Mushroom Burgers, Roasted Portobello Mushroom Sandwiches

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