Yes, yes, this is naughty, the lamb is studded with garlic and rosemary then slathered in butter and all the gorgeous juices drip down onto a bed of vegetables which in turn soften to a delicious fluff in the centre while forming crisp honeyed bits around the edges.
75ml (5 Tbsp) extra virgin olive oil 1 kg (2.2 lb) potatoes (I use desiree or agria), peeled and thinly sliced 2 large onions, peeled and thinly sliced 500g (about 1 lb) vine tomatoes or fleshy cherry tomatoes, sliced ½ cup dry white wine 2 Tbsp thyme leaves 1 small leg of lamb weighing around 1.7kg (about 3½ lb), shank removed 3 cloves garlic, peeled and cut into slivers 1-2 stems rosemary, broken apart into small sprigs 2 Tbsp (about 30g) butter, softened Sea salt
1 Preheat oven to 200°C (regular). Use a little of the oil to brush the insides of a thick china gratin dish, about 35cm long x 24cm wide 5-6cm deep. Put in the potatoes and season with salt and pepper. Next put in the onions and finally the tomatoes. Pour in the wine, then drizzle with remaining olive oil, season with more salt and pepper and strew with thyme.
2 Trim excess fat from lamb, then make a dozen or so incisions in the meaty parts. Stuff slivers of garlic and rosemary sprigs in the incisions. Rub lamb with softened butter and place it on a rack that will sit on top of the vegetables (a smallish cake rack will do the job). Sprinkle lamb with sea salt.
3 Bake lamb for 1 hour 10 minutes, turning it over twice during cooking. Transfer lamb to a board, drape loosely with tin foil and let it rest for 15 minutes before slicing. Meanwhile, if the potatoes have not browned, increase the heat a little and continue cooking until they are golden.
4 Slice lamb and serve with roasted vegetables.