1 Heat the oven to 200°C (180°C in a fan oven), 400°F, gas 6.
2 Blanch the leeks in salted, boiling water for for 2-3 min. Drain and wrap each piece in one or two slices of ham. Place in a baking dish.
3 Mix together the cream, stock, crème fraîche, eggs and cheese and season with salt, ground black pepper and nutmeg. Pour over the leak and the ham and bake for 25-30 min until golden brown. Serve garnished with chervil.