In a large bowl, mix together lamb, 1/2 of the garlic, cumin, coriander, cilantro, 1/5 of the yogurt, and coarse salt. Pat kofta mixture together into small balls about 2-inches in circumference.
In a large skillet, over medium-high heat, heat oil. Add kofta balls to the pan and heat on all sides until browned, about 10-12 minutes.
While kofta balls are cooking, in a medium-sized skillet with a tight fitting lid, bring broth to a boil. Add couscous, remove from heat, cover, and allow to stand for 10 minutes.
Fluff couscous with a fork. Add butter, onion, mint, remaining garlic, and table salt to taste. Toss together and set aside.
In a small bowl, whisk together the remaining yogurt, lemon juice and zest, parsley, and table salt to taste.
Serve kofta over couscous topped with the yogurt sauce.