For the lamb: Pre heat oven to 325 deg. F Mix spice rub and reserve. Mix all of the spices together to form rub. Remove 2 Tbsp. spice rub – mix with 1 tbsp. canola oil to form a paste. Trim excess fat from bottom of lamb shank – season each shank with ¼ of the paste. Pre heat skillet with 2 Tbsp. of the canola oil until starting to smoke. Add the lamb, turn down heat and sear for 3 - 4 mins. per side. Remove lamb from pan and reserve.
In same pan, add remaining canola oil and pre heat. Once hot, add the carrot, celery and onions. Turn heat down to medium, cook for 12 mins or until vegetables have browned. Add garlic and ginger, cook for 1 minute then add chopped tomato. Place browned vegetable mix into braising dish, place lamb meat side up on top of vegetable mix. Place mint on top of lamb shanks. Add broth to the frying pan – stir while scraping the bottom of the pan in order to pick up flavour and colour – bring to a boil, then turn down heat and add the remaining spice mix. Add to braising dish (the broth should cover approx. 2/3 of lamb shank). Cover with lid or tinfoil to tightly seal, place in oven and braise for 1 hour 45 mins.
Meanwhile, start the sweet potato mash. Pre heat oven to 400 deg. F. Coat sweet potatoes in canola oil, season with salt, pepper, and pinch of nutmeg. Lay sweet potatoes on tinfoil, skin side down, cover with foil to form ‘package,’ ensure tight seal. Place on a tray, roast for 45 mins. until soft. Remove sweet potatoes from the oven and allow to cool for 5 mins. Remove skin, place in bowl then add all of the other ingredients while still hot. Mix with a wooden spoon.
Pan roasted root vegetables: Add canola oil to pan, and heat– add vegetables, season with salt and pepper - cook over med. high heat for 3 mins. Add ½ cup vegetable stock, stir and cover – cook for 10 mins. until fork tender. Add fresh thyme leaves.
Once lamb is cooked, remove from pan and reserve. Strain vegetables from liquid and discard. Working with the cooking liquid, skim off any fat that rises to surface. Bring to a boil then simmer to reduce on medium heat until slightly thickened, about 10 -12 minutes.