Portobello Mushroom Burger

Ingredients

• 4 large portobello mushrooms
• 2 tbsp balsamic vinegar
• 2 tbsp soy sauce
• 2 garlic cloves, crushed
• 2 tsp smoked paprika
• 3 tbsp olive oil
• 120 g gruyere, sliced
• 4 burger buns
• 4 tbsp mayonnaise
• a couple of handfuls of rocket
• 1 red onion, sliced thin

Method

1. Scrape the gills out

   Wipe the mushrooms and scrape the dark gills out with a teaspoon. They hold a surprising amount of water and turn the bun grey and soggy if left in.

2. Marinate briefly

   Mix the balsamic, soy, garlic, paprika and oil and brush over both sides. Ten minutes is plenty — mushrooms are sponges and a long soak leaves them waterlogged rather than seasoned.

   10 min

3. Griddle gill-side up first

   Cook on a hot griddle gill-side up for 4 minutes so the juices collect in the cup, then turn. Turning too early tips all that liquid straight into the pan.

   8 min

4. Melt the cheese on

   Lay the gruyere over the mushrooms, cover the pan for a minute, and toast the buns alongside.

   2 min

5. Build

   Mayonnaise on both halves, then rocket, mushroom, and raw onion. Tip any juices from the pan over the bun rather than losing them.