These BBQ Portobello Mushroom Burgers are the perfect plant-based alternative to beef burgers or mock-meat burgers. Get the recipe below.

There's nothing like a BBQ in the summer. Sometimes as a vegan, it can feel as though you're limited to vegan burgers and sausages or vegetable kebabs. But, there are so many dishes you can cook on the BBQ that don't involve meat.
If you’re looking for a satisfying, meat-free burger that doesn’t compromise on flavour, these marinated BBQ portobello mushroom burgers are exactly what you need. With their naturally “meaty” texture, portobello mushrooms soak up a smoky barbecue marinade beautifully, making them the perfect plant-based alternative for your next cookout.
What takes this burger to the next level is the combination of vibrant, herby pesto and sharp, tangy pickled red onions. The richness of the mushroom pairs perfectly with the freshness of the pesto and the acidity of the onions, creating a balanced bite every time.
These BBQ Vegan Portobello Mushroom Burgers are juicy, savoury, and infused with that irresistible chargrilled flavour you only get from cooking on a BBQ.
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Ingredients
This recipe is as simple as it gets. Rather than mixing the mushrooms with other ingredients to form a patty (like my Mushroom and Black Bean Burgers) we use a marinated portobello mushroom by itself. For the marinated mushroom you'll need:
- Portobello mushrooms
- Balsamic vinegar
- Mixed herbs
- Garlic
- Olive oil
- Salt
You then need your burger buns and toppings. For the toppings you will need:
- Red onions
- White wine vinegar
- Vegan pesto
You could use store bought vegan pesto or one of these homemade versions:
Step-by-step-instructions

- Step 1: pickle the red onions

- Step 2: marinate the mushrooms

- Step 3: BBQ the mushrooms or cook over a hot grill

- Step 4: assemble the burgers in a bun spread with pesto and serve!
Variations
- Add grilled vegan halloumi for extra richness
- Spice it up with chilli flakes or sriracha in the marinade
- Use rocket for a peppery bite
- Try sun-dried tomato pesto for a deeper flavour twist
Equipment
You'll be pleased to know there's not much washing up with this recipe. All you need is:
- Grill pan or barbecue
- Mixing bowls
- Tongs
Top tip
Score the underside of the mushrooms lightly before marinating, this helps them absorb more flavour and cook evenly.
Frequently asked questions
Absolutely. Roast at 200C for about 20 minutes, turning halfway through.
It’s highly recommended because the marinade adds depth and prevents blandness.
You can marinate the mushrooms and pickle the onions ahead of time but the burgers are best cooked and assembled right before eating.

The recipe

Vegan BBQ Portobello Mushroom Burgers
Equipment
- Grill pan or barbecue
- mixing bowls
- Tongs
Ingredients
For the pickled onions
- 1 large red onion or 2 small
- 6 tablespoon white wine vinegar
- 0.5 teaspoon salt
For the mushrooms
- 4 portobello mushrooms
- 8 tablespoon balsamic vinegar
- 4 tablespoon olive oil
- 1 tablespoon dried mixed herbs
- 2 cloves garlic minced
To assemble
- 4 burger buns
- 4 tablespoon vegan pesto
Instructions
- Pour the white wine vinegar and salt over sliced onions and let sit for at least 30 minutes (longer for stronger flavour).
- In a bowl, whisk the olive oil, balsamic vinegar, garlic and mixed herbs. Coat the mushrooms well and let marinate for at least 20 minutes.
- Grill or pan-fry over medium heat for 4–5 minutes per side until tender and slightly charred.
- Spread pesto on the base bun, add the grilled mushroom and pickled onions.
- Top with the bun lid and enjoy!
Nutrition
More burger recipes
Serving suggestions
Serve these burgers with:
- Sweet potato fries or classic chips
- A fresh coleslaw or green salad
- Grilled corn on the cob











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