1 large carrot, roughly chopped
1 celery stalk, trimmed, roughly chopped
2 large floury potatoes, such as Maris Piper, sliced into 1cm/陆in-thick discs
1 large onion, roughly chopped
8 sprigs fresh thyme
2 tbsp plain flour
1 bay leaf
1 litre/1戮 pints beef stock
salt and freshly ground black pepper
3 tbsp olive oil
100驳/3陆辞锄 butter, melted
6 lamb chops, weighing approximately 500g/1lb 2oz in total