Duck Fillets in Pastry with Leek Sauce

The first magrets de canard (duck breast fillets) I ever ate were in a little restaurant in Paris; they were grilled pale pink, succulent and tender and it seemed to me to be the greatest luxury to be eating just the breast of the duck without struggling to get the meat off the bones of a leg joint. This recipe is another way of using breast fillets. If you like, you can make the rolls without using the fatty duck skin, though it does add extra flavour.