To achieve the perfect Chicken Shawarma, follow these step-by-step instructions:

Marinating the Chicken

1. Prepare the Marinade: In a large mixing bowl, combine the olive oil, lemon juice, minced garlic, cumin, paprika, turmeric, cinnamon, cayenne pepper, salt, and black pepper. Whisk until well blended. If using yogurt, add it to the mixture for extra tenderness.
2. Add the Chicken: Place the chicken thighs or breasts in the marinade. Ensure each piece is evenly coated. For best results, cover the bowl with plastic wrap and refrigerate for at least 4 hours, preferably overnight.

Roasting the Chicken

3. Preheat the Oven: Set your oven to 425°F (220°C). Line a baking sheet with aluminum foil or parchment paper for easy cleanup.
4. Arrange the Chicken: Remove the chicken from the marinade and arrange it on the prepared baking sheet. Spread the sliced onions over the chicken for added flavor.
5. Roast the Chicken: Place the baking sheet in the oven and roast for 25-30 minutes, or until the chicken is cooked through and golden brown. Use a meat thermometer to ensure the internal temperature reaches 165°F (75°C).

Preparing the Garlic Sauce

6. Make the Garlic Sauce: If making homemade toum, blend together garlic, oil, lemon juice, and a pinch of salt until creamy. Adjust seasoning to taste.
7. Rest the Chicken: Let the roasted chicken rest for 5 minutes before slicing it into thin strips.