To make the spice mix for the marinade, put the following into a pestle and mortar: sprig of cinnamon, cloves, cardamom seeds, pepper, salt and nutmeg shavings. Grind for a few minutes until the spices are broken down into a coarse powder.
Pour the yogurt, vinegar, crushed garlic, lemon, and powdered spice mix into a bowl. Cut or poke the fillets so they will marinade well, and then add the whole chicken fillets to the liquid and leave them to marinate for a few hours (or overnight) in the fridge.
When ready, remove the marinade from the fridge and cook on a BBQ, skillet, or roast in an oven. If you cook it in the oven, you’ll need to be careful not to overcook or dry out the meat.
Assemble the shawarma by putting your choice of sauce and the meat stuffing into pita bread.