Portobello Mushroom Burgers

These Portobello Mushroom Burgers are absolutely bursting with flavour! With a simple 4 ingredient marinade, these are sure to be some of the best veggie burgers you’ve ever had!

Portobello Mushroom Burger with caramelised onions, cheese, hummus, tomato and watercress

It wasn’t too long ago I uploaded my Beetroot Burger which went down an absolute treat! So, I thought I’d come back with another veggie burger for you.

Let’s welcome to the party our good friend Portobello Mushroom.

Portobello mushrooms make perfect burgers for a couple of reasons. Firstly, they’re big and juicy. I don’t know about you, but when someone says ‘mushroom burger’ I always think ‘it better be a darn big mushroom otherwise this ain’t gonna work.’ Portobellos can hold their own in a bun, trust me.

Second is that they take on flavour so well. Let’s welcome a few more friends to the party

Portobello Mushroom Marinade

  • Balsamic Vinegar
  • Soy Sauce
  • Worcestershire Sauce
  • Garlic
  • Olive Oil
  • Salt & Pepper

The combination of balsamic vinegar and soy sauce works wonders on so many things, not just including burgers. It’s something I learnt from Iceland’s head chef at an event and have used it on some many things when grilling. Most famously my Mexican Chicken Burger!

With the addition of Worcestershire sauce and garlic, you get a really deep ‘beefy’ and delicious flavour.

How to marinate portobello mushrooms - step by step photos

How to marinate Portobello Mushroom Burgers

  1. Clean your mushrooms with a damp cloth and remove the stalk.
  2. Add your marinade to a zip lock bag.
  3. Place in your mushrooms and move around with your hands to make sure they’re fully coated.
  4. Marinate for 30mins or as long as you have time for. Even 5 mins will make a difference.

Grilled Portobello Mushroom Burger

These beauties are perfect for the BBQ, but we’re in the thick of winter now so pan frying is where we’re at. I don’t recommend baking these as you won’t get the same caramelization and therefore, they’ll be laking in flavour.

Speaking of caramelization…

Portobello Mushroom with Caramelized Onions

With all burger recipes, the toppings/fillings are usually all down to preference. However, I usually claim a few ‘non-negotiables’ – caramelized onions is one of them.

A lot of the juices stay in the pan after you’ve fried the mushrooms, the onions will soak this up and taste beyond delicious once they’re fried. For proper caramelized onions, you want to fry them low and slow, but here I make quick caramelized onions (with a little help from a tsp of brown sugar). 

how to pan fry portobello mushrooms - step by step photos

How to fry Portobello Mushrooms

  1. Add your mushrooms face down to a pan over medium heat and fry for 4-5mins until soft.
  2. Flip mushrooms over.
  3. Add cheese and fry for another 4-5mins or until knife tender with the cheese melted. Remove from pan.
  4. Add onions & sugar and continue to fry until soft and caramelized

When it comes to what cheese to use, here I’ve used Swiss, but also regularly use Cheddar.

Portobello Mushroom Burger Fillings

Feel free to trade out the tomato or watercress, but the hummus, caramelized onions, cheese and TOASTED bun are a must ๐Ÿ™‚

Okay, let’s tuck into the recipe shall we?

Placing top bun on top of grilled portobello mushroom burger

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How to make Portobello Mushroom Burgers (Full Recipe & Video)

5 from 4 votes
Portobello Mushroom Burger with caramelised onions, cheese, hummus, tomato and watercress
Portobello Mushroom Burgers
Prep Time
15 mins
Cook Time
20 mins
Marinating Time
5 mins
Total Time
35 mins

These Portobello Mushroom Burgers are absolutely bursting with flavour! With a simple 4 ingredient marinade, these are sure to be some of the best veggie burgers you've ever had!

Course: Lunch
Cuisine: Vegetarian
Keyword: Portobello Mushroom Burgers
Servings: 4
Calories: 292 kcal
Author: Chris
  • 4 Portobello Mushrooms, stalks removed & cleaned as necessary
  • 2 tbsp Balsamic Vinegar
  • 2 tbsp Soy Sauce
  • 1 tbsp Worcestershire Sauce
  • 1 tsp Garlic
  • 1 tbsp Olive Oil
  • Salt & Black Pepper, to taste
  • 4 Burger Buns
  • 4 slices of Tomato
  • 4 tbsp Hummus
  • 4 slices of Cheese, here I use Swiss
  • 1 large Red Onion
  • 1 tsp Brown Sugar
  • 1 handful Watercress
  1. In a zip lock bag, combine your mushrooms with the marinade. Mix it around so all of the mushrooms are coated, then allow to marinate for 30mins, or as long as you have time for. Even 5mins makes the world of difference.

  2. Place your mushrooms facing down on a pan over medium heat and fry 4-5mins. Flip, then top with cheese and fry for another 5mins or until tender. Timings will depend on the size and shape of your mushrooms.

  3. Remove from pan, leaving any leftover juice, then add your onions. Fry until soft, then add sugar and continue frying until caramelised. For the best caramelised onions you want to fry low over a long period of time to release their natural sugars, but for convenience this works fine.

  4. Top your bottom burger bun with hummus, then watercress, then tomato, next with your mushroom burger, topped with your onions and finished with the top bun. Enjoy!

Watch how to make it!

Recipe Notes

a) Calories - Based on the assumption that all the marinade is used, which is of course an over estimate. Also including the toppings listed in the recipe card. Calories per burger.

Nutrition Facts
Portobello Mushroom Burgers
Amount Per Serving
Calories 292 Calories from Fat 120
% Daily Value*
Total Fat 13.28g 20%
Saturated Fat 5.455g 27%
Trans Fat 0.013g
Polyunsaturated Fat 1.492g
Monounsaturated Fat 5.52g
Cholesterol 19mg 6%
Sodium 1039mg 43%
Potassium 622mg 18%
Total Carbohydrates 32.79g 11%
Dietary Fiber 3.4g 14%
Sugars 11.08g
Protein 11.68g 23%
Vitamin A 27%
Vitamin C 14%
Calcium 28%
Iron 12%
* Percent Daily Values are based on a 2000 calorie diet.

For another delicious and easy portobello mushroom recipe, check out my Pizza Stuffed Portobello Mushrooms!

Pizza Stuffed Portobello Mushrooms with fresh parsley

If you loved this Mushroom Burger Recipe then be sure to Pin it for later! Already made it or got a burning question? Give me a shout in the comments below and pick up your free ecookbook along the way!


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  • Reply
    Danielle Wolter
    February 25, 2019 at 11:41 am

    these look incredible! I am loving that marinade and the onions on top. awesome alternative to your typical burger.

    • Reply
      February 25, 2019 at 3:43 pm

      Yup! I’m a total meat eater but still love these bad boys!

  • Reply
    Helen of Fuss Free Flavours
    February 25, 2019 at 12:09 pm

    Such an easy alternative for a veggie burger, bursting with delicioius flavours. A really good meal for everyone and great for any day of the week.

    • Reply
      February 25, 2019 at 3:46 pm

      Oh yes! These are perfect for all occasions!

  • Reply
    February 25, 2019 at 1:13 pm

    This recipe has so much flavor and it’s so easy! Love it!

    • Reply
      February 25, 2019 at 3:54 pm

      So much flavour! ๐Ÿ™‚

  • Reply
    February 25, 2019 at 1:24 pm

    I love portobello mushrooms! Such a wonderful way to add so much flavor.

    • Reply
      February 25, 2019 at 4:10 pm

      They’re the best aren’t they!? So versatile ๐Ÿ™‚

  • Reply
    February 25, 2019 at 1:26 pm

    Your photos are making me so hungry! I love how fully loaded this burger is!

    • Reply
      February 25, 2019 at 4:10 pm

      Thanks Sabrina! It’s so yum ๐Ÿ™‚

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