Quick bouillabaisse

Ingredients

• 30 grams butter
• 1 tablespoon olive oil
• 8 medium green prawns, peeled and deveined, heads and shells reserved
• 1 carrot, peeled and roughly chopped
• 3 large garlic cloves, bruised
• 1 tablespoon tomato paste
• 3 cups (750ml) fish stock
• pinch of saffron
• few chervil stems, leaves and stalks separated
• 1 leek, trimmed and sliced
• sea salt
• 1/3 cup (80ml) dry white wine
• 1 crab, quartered and cleaned
• 180 grams cod, skin and bones removed, cut into 2cm cubes
• 12 vongole or mussels
• cracked black pepper, to taste
• lemon cheeks and crusty bread, to serve