Portobello Mushroom Sandwich

Craft an epic Portobello Mushroom Sandwich, loaded up with balsamic marinated mushrooms, Swiss cheese, roasted red peppers, microgreens, and a secret special sauce! This super satisfying burger is perfect for a quick weeknight dinner or cookout!

This post is sponsored by American Dairy Association Mideast. As always, all opinions are my own.

The Anatomy of an Epic Portobello Sandwich

Portobello mushroom sandwich featured on a black plate with a wedge of Swiss cheese in the background.

If we ever opened a NeighborFood restaurant, our specialty would be sandwiches. Sandwiches are quick to make, but deliver BIG in flavor. They can be hot or cold, meaty or vegetarian, healthy or not so healthy a worthwhile splurge.

Over the years, we’ve experimented with dozens of different sandwich recipes, and we’ve learned a few things along the way. From a stack of gloriously gooey Apple Brie Grilled Cheese to the deceptively simple Turkey Avocado Sandwich, there are four key elements to crafting a perfect sandwich.

Today, we’re using them to build the ultimate Grilled Portobello Mushroom Sandwich. Here’s what you’ll need:

  • Good Bread– A soft, puffy Brioche roll is the perfect size and shape for a portobello mushroom burger.
  • Special Sauce– Plain mayo is fine, but all the best sandwiches have a special sauce. Whether it’s homemade pesto or chipotle mayo or the chive aioli we used here, a secret sauce is the little extra something something
  • Layers of Filling– We’ve got our tangy balsamic marinated portobello mushrooms, of course, but the best sandwiches have layers of different flavors and textures to enjoy. Here, the addition of roasted red peppers and crisp microgreens keep things interesting.
  • Cheese– Melty, gooey Swiss cheese pairs beautifully with mushrooms and makes this sandwich extra satisfying. Swiss and other cheeses like mozzarella and cheddar are also a great source of protein for a plant based sandwich. I used Guggisberg Baby Swiss for this recipe, which is an award winning cheese made right here in Ohio.
Portobello mushrooms in a glass casserole dish surrounded by ingredients for a sandwich.

What are portobello mushrooms?

If you feel intimidated by portobello mushrooms, don’t be! They’re actually just grown up versions of crimini mushrooms, and they work in a range of dishes. You can chop them up and use them in recipes like Parmesan Leek and Mushroom Pasta or Creamy Mushroom Soup.

They can also be left whole and grilled, pan seared, or roasted for use on top of salads, grains, or sandwiches. Their thick, meaty texture makes them the ideal base for a plant based burger!

How to Buy, Store, and Clean Portobello Mushrooms

When shopping for portobellos (or any mushroom, really), look for caps that are firm and dry, without any slimy or mottled spots. Store the mushrooms in the container you bought them in until you’re ready to cook them.

Use a slightly damp paper towel to wipe away any dirt from the surface of the mushrooms before cooking. You’ll also want to remove the thick, woody stem. I find the easiest way to remove the stem is to place a finger on either side of the stem, then use your other hand to gently work the stem back and forth until it pops out.

Balsamic marinade being poured onto a portobello mushroom.

Balsamic Marinated Portobello Mushrooms

Now, let’s talk marinades! Mushrooms are amazing vessels for marinades, soaking up all the savory umami flavors like a sponge. Here are the ingredients for my favorite mushroom marinade:

  • olive oil
  • balsamic vinegar
  • garlic
  • lemon juice
  • soy sauce
  • salt and pepper

How long do you marinate mushrooms?

I prefer to marinate mushrooms for at least 30 minutes for the best flavor, but they can go as long as 12 hours. Toss together the marinade in the morning, and it’ll be ready for you at dinner time! Be sure the marinade covers both sides of the mushroom. I prefer to marinate them gill side up, so the marinade can soak into it.

White casserole dish filled with four portobello mushroom caps in a balsamic marinade.

How to Grill Portobello Mushrooms

  1. Clean and oil the grill grates, either by rubbing with an oil soaked paper towel or spraying with cooking spray.
  2. Preheat the grill over high heat.
  3. Transfer and cook the mushrooms directly on the grill.
  4. Grill undisturbed for 3-4 minutes per side, or until mushrooms take on a rich, brown color.
  5. Add cheese slices on the mushrooms for the last minute of cooking time so they can get nice and melty.

How to Cook Portobello Mushrooms in a Skillet

If you prefer to cook your mushrooms on the stove top, grab a grill pan and heat it over medium high heat. Brush the grates with olive oil before adding the mushrooms, cooking each side for 3-4 minutes, or until well seared.

TIP: The cooked mushrooms can be brushed with extra marinade or placed back in the container they were marinated in until ready to serve.

Four grilled portobello mushrooms with melted cheese on top.

Making the Best Portobello Mushroom Sandwich

Black cast iron plate with a portobello mushroom sandwich, cheese wedge, and bowl of aioli on the side.
  1. Sauce. While the mushrooms are cooking, make the chive aioli by combining finely chopped chives, mayonnaise, garlic, and dijon mustard in a small bowl.
  2. Slather the sauce on both sides of the brioche bun.
  3. Stack with the grilled mushroom and melted Swiss cheese.
  4. Top with roasted red pepper slices and microgreens or sprouts for some crunch.
  5. Sandwich together and enjoy!
Sandwich stacked with a marinated portobello mushroom, red pepper slices, and microgreens.

Variations and Tips

Portobello mushroom sandwich on a brioche roll.

More Vegetarian Sandwich Recipes to Enjoy

Who says you need meat to make a great sandwich? Try these amazing plant based and vegetarian sandwiches next time you need a sandwich fix!

For more information about dairy nutrition and farming, visit www.Drink-Milk.com, and follow the American Dairy Association Mideast on Facebook, Twitter, Pinterest and Instagram.

Portobello mushroom sandwich featured on a black plate with a wedge of Swiss cheese in the background.

Portobello Mushroom Sandwich

Yield: 4 sandwiches
Prep Time: 15 minutes
Cook Time: 10 minutes
Additional Time: 30 minutes
Total Time: 55 minutes

A juicy balsamic marinated portobello mushroom forms the base of this delicious sandwich, loaded with roasted red pepper, Swiss cheese, and greens.


For the mushrooms:

  • 4 portobello mushrooms, stems removed
  • 2 Tablespoons olive oil
  • 1/4 cup balsamic vinegar
  • 3 cloves garlic, minced
  • 1 Tablespoon lemon juice
  • 1 Tablespoon soy sauce
  • 3/4 teaspoon Kosher salt
  • 1/2 teaspoon ground black pepper

For the aioli:

  • 1/2 cup mayonnaise
  • 1/4 cup roughly chopped chives
  • 1 teaspoon dijon mustard
  • 1 clove garlic
  • Squeeze of lemon
  • Salt, to taste

For the sandwiches:

  • 4 slices Swiss cheese
  • 4 brioche buns
  • 1 cup mixed greens and/or sprouts
  • 6 ounces of jarred roasted red bell peppers, sliced


  1. Make the marinade. In a glass measuring cup, whisk together the olive oil, balsamic, garlic, lemon juice, and salt and pepper. Place the mushrooms in a zip lock bag or shallow dish and pour the marinade over the top and undersides of the mushrooms. Cover and refrigerate, marinating for at least 30 minutes or up to 12 hours.
  2. Meanwhile, make the aioli. Combine the mayo, chives, dijon, garlic, and lemon in a food processor. Pulse until the chives are broken up into smaller pieces, stirring and scraping the bowl as necessary. Alternatively, chop the chives into small pieces with a knife and stir everything together in a bowl. Taste and season with salt as needed.
  3. To grill the mushrooms: Start with clean and oiled grates. Preheat the grill over high heat. Use tongs to transfer the mushrooms directly to the grill. Grill undisturbed for 3-4 minutes per side, or until mushrooms take on a rich, brown color. Place cheese slices on the mushrooms for the last minute of cooking time.
  4. To pan-fry the mushrooms: Brush a grill pan with a little oil, then heat over medium high heat. Add the mushrooms and cook undisturbed for 3-4 minutes per side or until mushrooms take on a rich brown color. Place cheese slices on the mushrooms for the last minute of cooking time.
  5. To serve: Spread each side of the brioche bun with the prepared aioli. Layer with the grilled mushroom and cheese, sliced bell peppers, and sprouts. Sandwich together and enjoy!

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