Cannelloni with Peas and Gorgonzola from Le Caprice by AA Gill and Mark Hix

Ingredients

• 30 g butter
• 150 ml Vegetable Stock
• 10 g mint leaves
• 1 small onion, peeled and finely chopped
• 1 kg frozen peas
• 90 g freshly grated Parmesan
• 1 ltr double cream
• salt
• freshly ground black pepper
• 120-150 g gorgonzola, cut into small cubes
• 16 pieces good-quality cannelloni or 16 lasagne sheets
• 1 egg yolk