Preheat the oven to 220°C, 200°C Fan, Gas Mark 7. Put a tray into the oven to heat up for 5 minutes.
Put 2 tablespoons oil into a bowl, add the garlic cloves and tip the potatoes into it. Toss well and season with salt. Tip just the potatoes into the roasting tray and roast in the oven for 25-30 minutes. After 15 minutes, add the garlic to the tray and turn the potatoes over.
Mix together the remaining oil and rosemary and brush all over the lamb cutlets and season them well. Around 10 minutes into the cooking time of the roasties, heat a frying pan over a medium heat. Rest the chops, rind-side down, into the pan and cook for around 2-3 minutes until golden. Lay them on their side, cover with a lid and cook for around 4 minutes until golden. Turn them over and cook on the other side, covering with a lid again.
Take the cutlets out of the pan and put on a warm plate. Cover and keep warm. Pour the stock into the pan and bring to the boil over a high heat. Simmer until reduced by half.
Steam the green beans or spinach in a pan, then toss in the butter and parsley. Divide the roasties and garlic between two plates, along with the greens, and then top with the lamb and spoon the sauce over the top.