Preheat oven to 140°C (or get a slow cooker ready).
Trim excess fat from the lamb (a small amount can remain for flavour and moisture). Cut into 4-5 big pieces. Brush all over with oil, then season with salt and pepper.
Heat a large frying pan on high. When hot, add lamb (you may need to do this in batches) and sear until browned. Turn over to brown the other side. Set aside in a casserole dish. Add carrot, anchovies, thyme, bay leaf and peppercorns.
Tip excess fat from the lamb pan. Reduce heat to medium, then add olive oil, onions and garlic cloves, then cook, stirring, for about 5 minutes or until starting to colour.
Add red wine, stock and tomato paste, then simmer for 1 minute. Stir in cornflour mixture and spoon everything carefully over the lamb.
If baking in the oven, cover the dish and bake for 3 hours. If using a slow cooker, cover and cook on high for about 6 hours or low for 8 (or see instructions for your slow cooker).
Remove from the oven and season with salt if needed. If the meat doesn't shred easily, cook for longer.
Remove meat from dish and shred into chunks. Strain the cooking sauce through a sieve or colander into a saucepan, then simmer the strained liquid for about 5-10 minutes or until reduced to a pouring sauce. Add the meat back in.
Serve ragu over mashed potato or kumara, pasta or potatoes. Sprinkle with fresh parsley.