2 garlic cloves, thinly sliced
750g/1lb 9oz floury potatoes, preferably Maris Piper, thinly sliced on a mandolin
2–3 fresh rosemary sprigs
salt and freshly ground black pepper
2 tsp freshly grated nutmeg
dash olive oil
butter, for greasing
200ml/7fl oz double cream
100²µ/3½´Ç³ú Emmental, grated
100ml/3½fl oz milk
2 x 6-bone racks of lamb, French-trimmed