Description

These smoky mushroom burgers feature large flat mushrooms stuffed with a flavorful mixture of mushroom stalks, roasted red peppers, thyme, breadcrumbs, sundried tomato paste, and smoked paprika. They are grilled on a barbecue until tender and served in crusty ciabatta rolls with roasted garlic mayo, caramelised red onions, fresh salad leaves, and a grating of cheddar or Manchego cheese, making for a delicious vegetarian alternative to traditional burgers.

Ingredients

Scale

Mushroom Burgers

4 large flat mushrooms
1 tbsp olive oil, plus extra for frying
2 roasted red peppers (from a jar), finely chopped
½ small pack thyme, leaves picked and chopped
50g fresh breadcrumbs
1 tbsp sundried tomato paste
2 tsp smoked paprika

Caramelised Onions

3 red onions, thinly sliced
1 tbsp golden caster sugar
1 tbsp sherry vinegar

Roasted Garlic Mayo

3 garlic cloves, unpeeled
50g good-quality mayonnaise

To Serve

4 crusty bread rolls (ciabatta)
Salad leaves
25g cheddar or Manchego, grated

Instructions

Prepare the roasted garlic mayo: Wrap the unpeeled garlic cloves in a foil parcel and position on a hot spot of the barbecue or bake in a hot oven for 20-30 minutes until very soft. Allow to cool, then squeeze the softened garlic out of their skins and mash with a fork. Mix this garlic purée into the mayonnaise and chill until ready to serve.
Make the mushroom filling: Remove the stalks from the mushrooms and finely chop them. Heat a drizzle of olive oil in a pan on the barbecue or hob and fry the chopped stalks for a few minutes until golden and soft. Stir in the finely chopped roasted red peppers, thyme leaves, fresh breadcrumbs, sundried tomato paste, smoked paprika, and season with salt and pepper. Cook the mixture for an additional 5 minutes, then set aside to cool slightly.
Prepare the mushrooms: Rub the mushroom caps with olive oil and season with salt and pepper. Top each mushroom cap with a quarter of the mushroom filling mixture. You can chill the filled mushrooms for up to 1 day if needed.
Cook the caramelised onions: Heat a little olive oil in another frying pan on the barbecue or hob. Add the thinly sliced onions and cook for 15 minutes until soft and golden. Add the golden caster sugar, sherry vinegar, and seasoning, then cook for another 5 minutes until the onions are caramelised and sticky. These can be chilled for up to 2 days.
Grill the mushrooms: Place the stuffed mushrooms on the barbecue with the stuffed side facing up. Close the lid or cover with foil and cook for 20 minutes until the mushrooms are soft and cooked through. Monitor the heat to prevent burning and move mushrooms to an upper shelf if necessary.
Toast the bread rolls: Split the ciabatta rolls and heat them on the barbecue until warmed through and slightly toasted.
Assemble the burgers: Spread a generous amount of the roasted garlic mayo on each bread roll, then layer with salad leaves, a stuffed mushroom, caramelised onions, and a grating of cheddar or Manchego cheese. Serve immediately and enjoy your smoky mushroom burgers.

Notes

Roasting the garlic on the barbecue infuses the mayonnaise with deep smoky flavor, but an oven can be used as an alternative.
The stuffed mushrooms can be prepared in advance and chilled to save time on the day of serving.
Keep an eye on the mushrooms during grilling to avoid burning; moving them to a cooler spot helps manage the heat.
Feel free to swap cheddar or Manchego for your preferred melting cheese if desired.
This recipe makes a great vegetarian option for outdoor BBQs and gatherings.

Prep Time: 20 minutes
Cook Time: 45 minutes
Category: Main Course
Method: Grilling
Cuisine: British

Keywords: smoky mushroom burgers, vegetarian burgers, grilled mushrooms, barbecue recipes, garlic mayonnaise, caramelised onions, ciabatta sandwich