Steps
- Heat the broiler to high. Trim 4 portobello mushrooms, rub with 1 teaspoon of sunflower oil, and place on a baking sheet.
- Broil for 3 minutes per side, until cooked but still firm.
- Mix 50g of grated vegetarian Gruyère, 1 crushed garlic clove, and 1 tablespoon of softened butter. Season with salt and pepper.
- Spoon the cheese mixture into the mushrooms and broil until melted. Split and toast 4 ciabatta rolls.
- Fill the rolls with 4 lettuce leaves, the mushrooms, 1 large sliced tomato, and ½ small thinly sliced red onion. Close the rolls.