Sorry for the delay in getting this to you...
This is a simplified recipe that I've developed myself. I've found that Lebanese kefta tends to be a bit spicier, and since I cook more Lebanese style than anything else, my recipe leans towards that. I leave the onion out because onion makes me ill. Some of the ingredients may surprise you
2 lb. ground beef or lamb
1 1/2 c seasoned bread crumbs.
2 cloves crushed garlic
1/2 c finely chopped parsley (or mint)
1 t. kosher salt
1/2 t ground pepper
1 oz Sadaf ground kebab seasoning (it's basically cumin, allspice, sumac, and some other things)
2 T Sriracha pepper sauce (sometimes I use more if I want them extra spicy

) If you're unfamiliar with it, it's that Vietnamese red pepper sauce with the rooster on the bottle that you find at all the Asian restaurants.
Dissolve the Sadaf seasoning in approx. 2 oz of water. It should have a loose paste-like consistency (not too thick). Knead together ingredients and seasoning. If the texture isn't enough to form "patties", add more bread crumbs a little at a time until it is. Cover and chill for an hour before forming the patties.
So yeah, a bit unusual, but I haven't had any complaints. I use a similar recipe for meatballs that go with an awesome Armenian yogurt soup. Sounds odd at first, but tastes amazing and has never failed to knock out colds.

(Pretty sure it's the spices and garlic in it).