squeeze of lemon juice
handful button mushrooms, wiped and quartered
1 medium green pepper, sliced
sprig of fresh tarragon (optional)
200ml/7fl oz chicken stock
1 heaped tbsp flour
2 tbsp butter, plus extra for frying
3 tbsp double cream
1 medium free-range egg, beaten
225g/8oz ready-made puff pastry
400g/14oz cooked chicken, shredded