Heat big frying pan and add butter untill foaming.

Add shallot and garlic, fry for several minutes.

Add chicken and fry till coloured all over.

Add mushrooms and fry on high for 3 minutes, or until soft.

Add madeira and flambe.

Add chicken stock and simmer, add tarragon and cream and simmer for 5 minutes.

Season and taste.

Transfer to a pie dish and cover with puff pastry, brush with egg yolk.

Cook in oven, gas mark 6 for 20 minutes.