500g/1lb 2oz chestnut mushrooms, halved or quartered if large
1 tsp garlic powder (or 1 garlic clove, crushed)
1 onion, finely chopped
4 tsp plain flour
1 tsp Worcestershire sauce
350ml/12fl oz beef stock (made with 1 beef stock cube)
salt and freshly ground black pepper
1 tsp dried mixed herbs
3 tsp sunflower oil
1 tbsp tomato pur茅e
1 tsp milk
320g/11陆oz sheet ready-rolled puff pastry (you will only use half)
250g/9oz thin frying steaks, cut into roughly 2cm/戮in pieces