You will need Leeks, Milk, Flour, Mustard powder, 2 Lemons, 2 or 3 Boiled Eggs, Parsley and Breadcrumbs.
Steam the leeks for a few minutes Make your lemon sauce (melt butter, add flour and 1 teaspoon of mustard powder. cook for 2 minutes. add milk very slowly stirring all the time. Return to the heat when thickened. Add juice and rind of 1 lemon, stirring all the time. Season.) Meanwhile: chop the eggs. Melt a tablespoon of butter. Add 3tbsp of bread crumbs, 1 tbsp of parsley, chopped eggs, grated rind and juice of the other lemon. Sauté this gently for 3 or 4 mins. Pour sauce over leeks and add the topping mix.