Preparation: 5 minutes + marinating Cooking: 15 minutes
2 tbsp olive oil
2 tbsp balsamic vinegar
1 clove garlic, crushed
4 Portabello mushrooms, stalks trimmed
100g creamy blue cheese such as Gorgonzola (or leave out for vegan)
6 small rolls, sliced horizontally
Your choice of lettuce, tomatoes, onion etc to serve
Mix the olive oil, balsamic vinegar and garlic together with salt and pepper. Pour half into a dish that will hold all of the mushrooms. Put the mushrooms in and drizzle over the remaining dressing. Cover and leave to marinate for an hour, moving them around once or twice to make sure they’re coated.
When ready to cook, heat the grill and put the mushrooms on a shallow baking tray gill side down. Grill for 5 minutes, then turn and cook the other side for 2 minutes.
While they are cooking, put the watercress into a bowl and cover with boiling water, leave for 1 minute until wilted, then drain on some kitchen roll.
Once the mushrooms are cooked, fill each one with watercress and top with the cheese. Return to the grill along with the rolls, cut side up.
When the rolls are toasted and the cheese is bubbling, place a mushroom inside each roll to make the burgers and serve immediately with your choice of fillings.