Preheat your oven to 325°F (160°C).
Make small incisions all over the lamb leg or shoulder and insert slices of garlic into the cuts.
Rub the lamb with olive oil, salt, black pepper, cumin, and paprika.
Place the lamb in a large roasting pan.
Arrange the onion quarters and carrot pieces around the lamb.
Add the rosemary and thyme sprigs.
Pour the water or lamb broth into the bottom of the roasting pan.
Cover the roasting pan tightly with aluminum foil.
Roast in the preheated oven for 3.5 to 4 hours, or until the lamb is tender and easily pulls apart with a fork.
If you prefer a crispy exterior, remove the foil during the last 20-30 minutes of cooking.
Increase the oven temperature to 400°F (200°C) and roast until the lamb is browned and crispy on the outside.
Let the lamb rest for about 15 minutes before carving.
Enjoy your meal!