2 large carrots, cut into chunks
2 large celery sticks, finely chopped
6 large garlic cloves, finely chopped
150g/5½oz button mushrooms, kept whole
2 large brown onions, finely chopped
1 fresh thyme sprig
300ml/10fl oz chicken stock
plain flour, for dusting
3 tbsp plain flour
salt and freshly ground black pepper
3–4 tbsp vegetable oil, plus more for drizzling if needed
1 free-range egg, beaten, to glaze
350g/12oz ready-rolled puff pastry, for the lid
350g/12oz ready-rolled shortcrust pastry, for the base
900g/2lb rump steak, cut into bite-sized chunks
500ml/18fl oz Irish stout (such as Guinness)