James Martin's chicken and wild mushroom pie recipe

INGREDIENTS

• 375 ready-rolled all-butter puff pastry
• g egg, beaten
• 1 x 1.5kg (31b 4oz) chicken
• 1 onions, peeled and finely chopped
• 2 bay leaf
• 1 olive oil
• 1 butter
• tbsp plain flour
• 75 wild mushrooms (such as chanterelle, cep, tompette, girolle or oyster)
• g white wine
• 2 double cream
• tbsp sprigs of tarragon, leaves only
• 350 salt and black pepper