This Portobello mushroom burger with blue cheese and caramelized onions is loaded with incredible umami flavors. Prepared with an easy 40-minute hamburger bun, this vegetarian burger has it all. Even meat-eaters love it!

This Portobello mushroom burger with blue cheese and caramelized onions is loaded with incredible umami flavors.

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Ever since I’ve known my husband, I have had Portobello mushrooms in my life. Growing up in the United States, he knew this type of mushroom way before me and has always been ridiculously obsessed with it. He loves it cooked and topped with blue cheese – and so do I.

This Portobello mushroom burger with blue cheese and caramelized onions is loaded with incredible umami flavors.

Now keep this perfect combo (Portobello and blue cheese), and make it a burger! Portobello mushroom burger is to me the ultimate veggie burger. This comes from the fact that Portobello mushrooms have a meaty flavor and texture when cooked, which makes them a great meat substitute, with no fat, sodium or cholesterol.

Why you’ll love this Portobello mushroom burger?

  • A great chewy, meat-alike texture
  • Loaded with umami flavors
  • A quick and easy homemade burger bun
  • Even non-vegetarians love it!
This Portobello mushroom burger with blue cheese and caramelized onions is loaded with incredible umami flavors.

What is Portobello mushroom?

Portobello mushrooms are an extremely large, dark brown mushroom, mainly produced in the United States. They are loaded with umami flavors and have a chewy meat-alike texture. Because of this, they usually have success among both vegetarians and meat-eaters!

The main recipe ingredients

  • Portobello mushrooms. Obviously! Choose them small to medium size, so they fit nicely in a bun.
  • Blue cheese. Any kind will do (Danish Blue and Stilton are my favorites in this recipe).
  • Teriyaki sauce + balsamic vinegar. Together, they create the incredible umami flavors in these Portobello mushroom burgers.
  • Red onions. They’re caramelized with balsamic vinegar, giving them a sweet, tangy flavor.

Then of course, you’ll need the ingredients for the homemade buns (flour, yeast, vegetable oil, sugar, egg). For the full list of ingredients, head over to the recipe card below.

This Portobello mushroom burger with blue cheese and caramelized onions is loaded with incredible umami flavors.
This Portobello mushroom burger with blue cheese and caramelized onions is loaded with incredible umami flavors.

Key steps to prepare Portobello mushroom burger from scratch

  1. Start with making the easy homemade buns. I promise it doesn’t require much effort and the result is way more satisfying than store-bought burger buns (see more details in the dedicated section below).
  2. Prepare the caramelized onions, by cooking together red onions, balsamic vinegar and a little bit of sugar, until soft and tender.
  3. Let the Portobello mushrooms marinate in the teriyaki-balsamic sauce, then grill and top with blue cheese. Cook some more, until the cheese is melted.
  4. Now assemble the burgers! Open up the buns, then layer some lettuce, beans (if using), caramelized onions and Portobello with blue cheese!
This Portobello mushroom burger with blue cheese and caramelized onions is loaded with incredible umami flavors.
This Portobello mushroom burger with blue cheese and caramelized onions is loaded with incredible umami flavors.
This Portobello mushroom burger with blue cheese and caramelized onions is loaded with incredible umami flavors.
This Portobello mushroom burger with blue cheese and caramelized onions is loaded with incredible umami flavors.

Pro tips and quick variation

The key to scrumptious Portobello mushrooms is to marinate them in the teriyaki sauce for 15 minutes or longer (30 minutes is perfect!). You can grill the mushrooms on the stove or roast them in the oven at 400°F (200°C) until tender, about 15 to 20 minutes. Add the blue cheese, then return the Portobello mushrooms to the oven until the cheese melts, about 3 to 5 additional minutes.

A quick and easy burger bun recipe!

If you feel lazy about making homemade burger buns, I hear you! Here’s a quick and super easy burger bun recipe that is ready in 40 minutes, from start to finish. You could even knead the dough by hand – it only takes 3 to 5 minutes! And let me tell you, there’s nothing to compare with freshly baked buns when making burgers. So make yourself a favor, and go the extra mile by making these 100% homemade burger buns ; you’ll thank me later!

What to serve with Portobello mushroom burgers?

A side of sweet potato fries is always my best bet to serve with burger. For a healthier version, simply add a side of greens (arugula, spring mix, lettuce, etc.).

This Portobello mushroom burger with blue cheese and caramelized onions is loaded with incredible umami flavors.

Other incredible mushroom recipes:

More veggie burger recipes you’ll love:

This Portobello mushroom burger with blue cheese and caramelized onions is loaded with incredible umami flavors.
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Portobello Mushroom Burger

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This Portobello mushroom burger with blue cheese and caramelized onions is loaded with incredible umami flavors.
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  • Author: Delphine Fortin
  • Prep Time: 1 hour 30 mins
  • Cook Time: 15 mins
  • Total Time: 1 hour 45 minutes
  • Yield: 6 burgers 1x
  • Category: Mains
  • Cuisine: American
  • Diet: Vegetarian

This Portobello mushroom burger with blue cheese and caramelized onions is loaded with incredible umami flavors. Prepared with an easy 40-minute hamburger bun, this vegetarian burger has it all. Even meat-eaters love it!

Email me this recipe

We’ll send it straight to your inbox, along with weekly food inspiration!

Ingredients

Scale

For the burger buns (makes about 6 buns):

  • 2 Tablespoons active dry yeast
  • 1 cup + 2 Tablespoons (270 ml) warm water
  • ⅓ cup (80 ml) vegetable oil
  • ¼ cup (50g) sugar
  • 1 large egg
  • 1 teaspoon salt
  • 3 to 3 ½ cups (360-420g) all-purpose flour
  • 1 yolk, for brushing
  • 1 Tablespoon sesame seeds

For the Portobello filling:

  • 6 Portobello mushrooms
  • 4 Tablespoons teriyaki sauce
  • ½ cup (120 ml) balsamic vinegar, divided
  • 7 ounces (200g) blue cheese
  • 2 medium red onions, finely sliced
  • ¼ cup (60 ml) olive oil
  • 1 Tablespoon brown sugar
  • Fresh lettuce leaves, for garnishing
  • ½ cup (90g) cooked kidney beans (optional)*
  • ⅓ cup (75g) tomato sauce (optional)*

Instructions

For the burger buns:

  1. Preheat the oven to 425°F (220°C), and line a large baking sheet with parchment paper.
  2. In a large bowl, dissolve yeast in warm water. Add oil and sugar, and let sit for 5 minutes. Add the egg, salt and enough flour to form a soft dough.
  3. Turn onto a floured surface, and knead by hand until smooth and elastic, about 3-5 minutes. Divide into about 6 equal parts, and shape each into a ball. Place them a few inches apart onto the prepared baking sheet, cover and let rest for 10 minutes.
  4. Generously brush each bun with the beaten yolk, sprinkle with sesame, and bake for 8-12 minutes or until golden brown. Remove from pans and transfer to wire racks to cool.

For the filling:

  1. For the caramelized onions. Heat olive oil in a large skillet over medium heat. Once hot, add the onions and cook until translucent. Add ¼ cup (60 ml) balsamic vinegar, brown sugar, and cook uncovered for about 20 minutes, stirring occasionally. The onions are ready when they are soft, slightly sticky and caramelized.
  2. For the Portobellos. Combine teriyaki sauce and the remaining ¼ cup (60 ml) balsamic vinegar in a shallow dish. Place mushroom caps, gill-side up, and let marinade for 15 minutes or more.
  3. In a large skillet, heat olive oil over medium-high heat. Cook the Portobello mushrooms about 6-7 minute per side, until cooked through and perfectly tender. Top each mushroom with blue cheese and continue to cook until just melted, about 2 minutes.**
  4. Heat the bean-tomato sauce (optional)* in a small saucepan over medium heat.
  5. For assembling. Cut the buns in half. Add some lettuce, caramelized onions and beans (if using)* on the cut side of each bun. Now add a Portobello mushroom with blue cheese, and cover with the top bun. Enjoy!

Notes

* These are the two ingredients you need to make the bean-tomato sauce (entirely optional in the recipe). You can skip the sauce and simply assemble your burger with lettuce, caramelized onions and Portobello mushrooms.

** Alternatively, you can grill the mushrooms in the oven at 400°F (200°C) until tender, about 15 to 20 minutes. Add the blue cheese, then return the Portobello mushrooms to the oven until the cheese melts, about 3 to 5 additional minutes.

Cheese, Fall, Family-Friendly, Mushrooms, Sandwiches, Vegetarian, Winter

Did you make this recipe?

Lastly, if you make this Portobello Mushroom Burger, be sure to leave a comment and give this recipe a rating, letting me know how you liked it. And of course, don’t forget to tag me on Instagram! Thank you and enjoy!