Step 1

Fire up the barbecue ready for direct cooking, adding a little smoking wood to the fire.

Step 2

Toast the pine nuts in a small frying pan set over the fire. Transfer to a pestle and mortar and grind coarsely. Add most of the chopped basil (saving a sprinkle to garnish), the parmesan, garlic, sprinkle of Maldon salt and pound to a rough paste. Stir in the olive oil and vinegar and season to taste with Maldon salt and pepper.

Step 3

Drizzle the mushrooms with olive oil, season well with Maldon salt and pepper, then rest them on the grill bars directly over the fire, gill-side down. Shut the lid and cook for 10 minutes, or until softening.

Step 4

Transfer, gill-side up, to a fireproof roasting tin and use a small sharp knife to ease out the cooked stems. Chop the stems and scatter into the hollows of the mushrooms.

Step 5

Spoon the beans equally into the hollows of the mushrooms. Top each mushroom with 1–2 teaspoons of pesto and a slice of mozzarella.

Step 6

Sprinkle over the breadcrumbs and finish with a drizzle of olive oil, then slide the tin back over the fire. Shut the lid and cook for a further 10–15 minutes until the cheese is melting and the breadcrumbs are crisping up.

Step 7

Serve hot and bubbling from the grill, sprinkled with the remaining basil and a pinch of Maldon salt.