I have a feeling you are having feelings about this Portobello Mushroom Burger.

Stuffed Portobello Mushroom Burger with Cheese and Pesto in a Brioche Bun

Portobello mushrooms that are…

  • soaked in a quick but high-impact balsamic-soy marinade (a riff on my tried-and-true Grilled Portobello Mushrooms)
  • double stacked and stuffed with havarti cheese
  • slathered in pesto (and more cheese)
  • piled inside a fluffy brioche bun, and
  • topped with grilled onions and tomatoes

…tend to elicit one of two reactions.

Reaction One: GIMME.

Or

Reaction Two: Why are we calling a portobello mushroom a burger again?

Whichever camp you fall in—I grew up in the (meat) burger-loving Midwest, so even though I fall solidly in the Reaction One group, I can hear Reaction Two’s concerns—try this Portobello Mushroom Burger recipe anyway.

Even without meat, this Portobello Mushroom Burger is savory, satisfying, and good and messy, the way a proper burger should be.

The pesto makes the burgers fresh, unique, and bright, the prep and cleanup are a breeze, and it’s healthy without tasting overly so.

My #1 Trick to Making the Very Best Portobello Mushroom Burger

So, you’ve seen other Portobello Mushroom Burger recipes. Maybe you’ve made one or two at home or ordered them on a menu.

Here’s why I like this particular Portobello Mushroom Burger the best.

A cross-section of a Portobello Mushroom Burger stuffed with havarti

It is a STUFFED Portobello Mushroom Burger.

Whenever I’m creating a recipe, it is imperative to me that even though the recipe is healthy, it is 100% satisfying and stays true to the recipe’s intent and the feelings that led me to crave it in the first place.

While I’ve liked other portobello mushroom burgers I’ve tried, they tasted too “diet.”

My solution: double stack and stuff. Each Portobello Mushroom Burger “patty” is actually two portobellos, with a layer of cheese melted in between. (Those who clicked on this recipe seeking a vegan Portobello Mushroom Burger, you can swap a dairy-free cheese instead.)

I actually lifted the idea of stacking and stuffing the portobello mushrooms from Shake Shack, whose vegetarian burger does just this.

Shake Shack’s portobello burger is also breaded and deep fried, which I honestly found overkill. The burgers have a stellar flavor all on their own, no heavy excess breading required.

Cleaning portobello mushrooms for Portobello Mushroom Burgers

Portobello Mushroom Prep Tip

Whenever you are cooking with portobello mushrooms, I recommend removing the stems and gills first. The gills are edible, but they often contain bits of sand (not what I want in my burger), and because they are so black, they’ll turn whatever you are cooking them with a dark color.

To remove the gills, gently twist off the stem. Lay the mushroom cap-side down (gill-side up). Use a small spoon to scrape away and discard the dark gills. You are ready to cook! 

How to Cook Portobello Mushroom Burgers 

Step 1: Portobello Mushroom Burger Marinade

Start here with just three important ingredients:

  • Soy Sauce. For a deep, umami flavor.
  • Balsamic Vinegar. For a little brightness and tang.
  • Garlic. A mushroom’s flavor BFF.

For the max flavor impact, I recommend marinating the portobello mushrooms for at least 30 minutes or up to two hours. Use the time while you wait to prep any toppings or sides.

Step 2: Portobello Mushroom Cooking Methods

While the outdoor grill is an ideal option for summer months, you have plenty of other options to make this recipe.

  • Portobello Mushroom Burger on the Stove. Use an indoor grill pan like this one.
  • Pan-Fried Portobello Mushroom Burger. Another stove option: Cook the mushrooms in a lightly oiled cast-iron or similar heavy-bottom skillet.
  • Portobello Mushroom Burger in the Oven. Roast the mushrooms at 400 degrees F until tender, about 15 to 20 minutes. Add the cheese, stack, then return the burgers to the oven until the cheese melts, about 3 to 5 additional minutes.

For outdoor grill directions, follow the recipe as directed.

A deconstructed Portobello Mushroom Burger

Step 3: Toppings

Use this recipe as guideline to create the Portobello Mushroom Burger of your dreams!

  • Portobello Burgers with Pesto. This is our FAVE. Ben went so far as to call the pesto a “must” because it adds so much additional freshness. I used a good-quality store-bought pesto and can only imagine how incredible the burgers would be with homemade.
  • Add an Egg. If you love your regular burgers with an egg, you’ll adore your Portobello Mushroom Burger with one too.
  • Vary the Cheese. I opted for havarti, because it melts nicely and goes well with pesto, and I find its flavor more interesting that mozzarella. For next time, I’m already planning a Portobello Mushroom Burger with goat cheese (swooooon!). If goat cheese isn’t your thing, try your Portobello Burger with feta.
  • Extra Veggies. Fresh tomatoes and a slice of grilled red onion make these Portobello Mushroom Burgers sublime.

How to Serve Portobello Mushroom Burgers

  • In true burger spirit, we picked brioche buns for our Portobello Mushroom Burgers. Brioche is supple and soft, so it doesn’t overwhelm the mushrooms the way a thicker, chewier bun would. Soft whole wheat burger buns would be delicious too.
  • If you are looking to save Portobello Mushroom Burger calories, you could wrap the burgers in butter lettuce leaves.
  • These Portobello Mushroom Burgers also work nicely as a knife-and-fork situation, alongside a bed of crisp greens.

A fully loaded Portobello Mushroom Burger

What to Serve with Portobello Mushroom Burgers

A few of my favorite sides:

How will you serve up your Portobello Mushroom Burger? If you try this recipe, let me know how it turned out (and what toppings you picked!) in the comments section below.

5 from 2 votes
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Portobello Mushroom Burger

Yield: 2 burgers
Prep Time:
5 mins
Cook Time:
10 mins
Total Time:
45 mins
BEST Portobello Mushroom Burger! An easy balsamic marinade adds incredible flavor. Stuffed with cheese, rich, and savory. Even meat lovers cannot resist!

Ingredients

  • 2 tablespoons low-sodium soy sauce
  • 2 tablespoons balsamic vinegar
  • 1 tablespoon extra-virgin olive oil
  • 3 cloves garlic — minced
  • 1 1/2 teaspoons Italian seasoning
  • 1/2 teaspoon black pepper
  • 4 portobello mushroom caps — cleaned with underside stems and gills removed
  • 4 thin slices havarti cheese — or swap provolone or baby Swiss

For serving:

  • Whole wheat or brioche hamburger buns
  • Sliced red onions
  • Pesto
  • Sliced tomato
  • Arugula

Instructions

  1. In a large ziptop bag, combine the soy sauce, balsamic vinegar, oil, garlic, Italian seasoning, and black pepper. Add the mushroom caps and seal the bag, removing as much air as possible. Gently swish the marinade around the mushrooms, then place the bag in a shallow dish. Allow the mushrooms to sit at room temperature for at least 30 minutes while you prepare any desired toppings, or refrigerate for up to 1 hour. Turn the bag once or twice while the mushrooms sit so that they are coated evenly.

  2. Heat an outdoor grill or indoor grill pan to medium heat. Once hot, brush the grate lightly with oil to prevent sticking. or lightly spray the grill pan with nonstick spray.

  3. Remove the mushrooms from the marinade, shaking off any excess. Reserve the marinade in the bag for basting. Grill the mushrooms on both sides until tender, about 10 minutes total, brushing them with the marinade several times throughout.

  4. When the mushrooms are in their final minute of cooking, turn two of them so that their undersides (the ones that previously had the gills and stem) are facing up. Top each with 1 slice of cheese, then stack a second mushroom on top, gill-side down, so that the cheese is in the middle. Place a second slice of cheese on top. Reduce the heat to low and cook just until the cheese is melted.

  5. During the last few minutes of cooking, if desired, grill sliced onions and toast the buns. To assemble, spread a thin layer of pesto on the cut sides of each bun. Place the arugula on the bottom bun, then top with a grilled portobello mushroom stack, onion, and tomato. Add the top bun. Enjoy immediately.

Course: Main Course
Cuisine: American
Keyword: Grill, Oven, Portobello Mushroom Burger, Stove, Stuffed, Vegetarian

Nutrition Information

Amount per serving (1 burger, without bun or topping) — Calories: 140, Fat: 8g, Saturated Fat: 1g, Cholesterol: 2mg, Sodium: 569mg, Potassium: 695mg, Carbohydrates: 13g, Fiber: 3g, Sugar: 7g, Protein: 5g, Vitamin A: 25%, Vitamin C: 1.4%, Calcium: 49%, Iron: 1.5%

Did you try this recipe? I want to see! Follow Well Plated on Instagram, snap a photo, and tag it #wellplated. I love to know what you are making!