To make the pastry, sift flour onto work surface. Make a well in centre and put in water and salt, scattering butter in small dabs around edge. Knead all ingredients together as quickly as possible, keeping dough cool. Roll into sausage shape, wrap in waxed paper and put in refrigerator to cool for 2 hours.

To make filling, finely chop cooked chicken.

Melt half of butter in saucepan, saute rice briefly, stirring well, then add sufficient water to cover rice. Add 1/2 tsp salt, stir once and leave to cook for 20 minutes over low heat until all water is absorbed

Trim and wipe mushrooms, then slice thinly. Melt remaining butter in sufficiently large pan to fry mushrooms; cook over a low heat until all juices have evaporated. Season with 1/2 tsp salt and pepper.

Peel and chop hard-boiled eggs.

Put rice into a bowl together with chicken, mushrooms and eggs, mixing well and adding cream.

Wash and dry dill and parsley. Cut dill into short feathers, finely chop parsley. Add to filling and season again with salt and pepper to taste.

Preheat oven to 220°C (425°F) Gas Mark 7. Grease tin with butter.

Thinly roll out half the pastry on floured work surface into a circle, a little larger than the tin. Roll out the other half to a circle, exactly the size of the tin. Put larger circle into tin, pressing down well onto base and up sides. Prick base with fork. Spread filling on base and smooth top. Lay pastry lid on top and seal edges together. Prick top to allow steam to escape during baking.

To make the glaze, beat egg yolk with remaining cream and brush over pastry. Bake in middle of oven for 30 minutes until nicely browned.

Serve either hot or cold.