1) Take a roasting bag and place the leeks along with water.
2) Tie the bag loosely with a string and cook on power for 6 minutes on power.
3) Sieve and reserve the liquid.
4) Take a serving dish and arrange the leeks on it.
5) Make a paste of cornflour with milk.
6) Make the sauce upto 350 ml by adding the reserved liquid and the milk.
7) Cook the sauce for a 6 minutes on power, season to taste, and then add grated cheese to it.
8) Pour the sauce over the leeks, garnish with the remaining cheese, and grill to brown.