Preheat your oven to 325°F.
In a small bowl, mix together the minced garlic, olive oil, cumin, coriander, smoked paprika, cinnamon, salt, and black pepper to form a paste.
Rub the spice paste all over the lamb, ensuring it is well coated. Place the lamb in a roasting pan and pour the lemon juice over it.
Cover the roasting pan with aluminum foil and roast in the preheated oven for 2 hours.
After 2 hours, remove the foil and continue roasting for an additional 30-45 minutes, or until the lamb is tender and the internal temperature reaches 145°F for medium-rare.
Once done, remove the lamb from the oven and let it rest for 15 minutes before slicing. Serve with yogurt on the side and garnish with fresh parsley.