Special equipment: a potjie pot (three-legged round cast-iron pot) or other heavy cast-iron pan
Prepare a charcoal or wood fire in a grill.
In a large bowl, mix together the flour, coriander, cumin, garlic and rosemary seasoning and paprika. Mix the lamb neck with the flour and spices to coat, then set aside.
Place the potjie pot or cast-iron pan directly on the fire. Heat the canola oil in the pot, add the lamb and brown the meat for 4 minutes. Add half of the garlic, the celery, onions and green peppers and saute for 5 minutes. Add any of the remaining seasoned flour from the meat and cook out for a minute--this will help thicken the stew. Stir in the canned tomatoes and tomato paste. Pour in the stock just to cover and season with salt and pepper. Bring the mixture to a simmer. Cover with the lid and simmer, stirring every 20 to 30 minutes and replenishing with water if needed, until the meat is tender, about 2 hours. Throughout the cooking time check that the heat is not too high and adjust as necessary.
Add the carrots, potatoes and the rest of the garlic and cook until the veggies are cooked but still firm, a further 20 minutes. Serve with crusty bread and sprinkle with parsley.
Traditionally this is cooked in a cast-iron pot over coals outdoors, but you can cook it in any heavy-based pan and it would work over a barbecue or outdoor range or on the stove indoors.