One can always buy the spices mix 'shawarma spice mix'. also, I suppose it will be available on line.
Olive oil, vinegar, onion, garlic and spices: cardamom ( هال)cinnamon, miskeh, (مسكه( cloves, peppercorns, (turmeric is my addition), mahlab(محلب)and of course salt. You can get the spices mix ready.
In a food processor, Put the onions, the garlic, the spices. Reduce to a coarse paste. Transfer to a big bowl. Add olive oil and vinegar. It is the marinade.
This is the marinade.
Add the meat cut into strips like above
Mix well and Leave overnight. Or you can freeze them until needed.
After at least 12-24 hrs and before cooking. Strain them from extra liquid
Put in a very hot skillet
In 1-2 mins the meat will give out its juice. At this point
Cover and cook in its juice for 5 mins
5 mins after the juice is reabsorbed by the meat. Continue to dry it stirring non stop
It will dry out and when it starts sticking on the pan
Deglaze by 1TBsp of lemon juice. Or just water. It will give a creamy consistency. Divine and flavorful
Serve. This is one proposition. The garnish is traditionally onions tomatoes parsley and tahini sauce
Here I minced parsley, mixed it with the tahini (actually it is a dip presented in the traditional mezze). Red onions cut into wedges and sprinkled with sumac and the tomato wedges
Another disposition . It all depends on the kind of meal you are serving, and of course the amount.
Individual serving for a seated dinner??
Sprinkle sumac for the look
Personally, for big party buffet, I serve it as a salad. So, guests can be served much quicker. So ??? Up to you