Let's start by making the meat mix for the patties. In a bowl, take the ground meat. To this, add salt, black pepper, cumin, nutmeg, oregano, garlic, red onion and lime juice. Mix well.
Make four equal portions of the meat. Shape them into long and thin patties so they fit the flatbread. If you want to know the exact dimensions, try to keep them 6 inches in length, 3 inches in width and thickness of about 1/2 inch.
After this is done, refrigerate them for an hour to marinate, so the ingredients sit well with each. This is important and shouldn't be overlooked.
The method of cooking the patties is up to you. You can grill, pan-grill, or fry them. In any case, preheat the grill, pan-grill, or skillet.
If grilling, brush the patties with oil on both sides. For frying, take oil in a pan and fry each side for about 3-4 minutes.
Then, begin assembling the sandwiches. Take the flatbread and spread tzatziki sauce on the center of it.
Put lettuce, sliced tomatoes and onions on it.
Lay the patty on this bed of sauce and vegetables and fold the bread blanketing the lamb in the middle.
Now, all there's left to do is serve and enjoy.