Ingredients

• 80ml/3fl oz olive oil
• 2 large onions
• finely sliced
• 6 large field mushrooms
• peeled and trimmed
• salt and freshly ground pepper
• 30g/1oz butter
• 2 garlic cloves
• roughly chopped
• 100ml/3½fl oz olive oil
• 225g/8oz mature cheddar or gruyere cheese
• grated
• 1 tsp wholegrain mustard
• 1 garlic clove
• crushed
• 1 free-range egg
• beaten

Directions

• Preheat the oven to 180C/355F/Gas 4 and preheat the grill to its highest setting.
• For the caramelised onions
• heat the oil in a frying pan over a very low heat. Add the onions and gently fry for 45 minutes
• stirring regularly
• until the onions are caramelised
• golden-brown and sweet.
• Meanwhile
• for the mushrooms
• place the mushrooms in a baking dish and season with salt and freshly ground black pepper. Sprinkle with the butter and garlic
• then pour over the olive oil. Transfer to the oven to bake for 10-12 minutes
• until softened slightly.
• For the rarebit
• place the cheese
• mustard
• garlic and egg into a bowl and mix together well.
• Remove the mushrooms from the oven. Spoon over the caramelised onions and some of the rarebit mixture
• pressing this topping into each mushroom.
• Transfer the mushrooms to the hot grill and cook until the cheese bubbles
• melts and becomes golden-brown.
• To serve
• place a large cheese-coated mushroom onto each of six plates.