Set the oven at 200C/gas mark 6. Put two duck legs in a roasting tin, no fat or oil needed, season lightly and roast for 40 minutes until the skin is lightly crisp. Pour off any fat that appears in the roasting tin. Place the duck on a chopping board and tear off the skin and set aside. Remove the flesh from the legs and cut into pieces just large enough to get on your spoon.
Put the roasting tin over a moderate heat, pour in 1.5 litres of chicken or vegetable stock, then bring to the boil, stirring to dissolve any tasty bits on the tin. Simmer the stock for 15 minutes to reduce it slightly then add 100g of udon noodles and two handfuls of dried dulse or other thin seaweed. Continue cooking for 2 or 3 minutes until the udon is tender and the dulse soft. Add the reserved duck meat and check the seasoning.