In a large bowl, combine Greek yogurt, olive oil, lemon juice, minced garlic, cumin, coriander, paprika, turmeric, cinnamon, salt, and pepper. Mix until well blended. Add the chicken and coat thoroughly. Cover and refrigerate for at least 1 hour.

Preheat your grill pan or outdoor grill to medium-high heat (about 400°F). Clean and grease the surface to prevent sticking.

Grill the marinated chicken for 5–7 minutes on each side until fully cooked. Rest the chicken for 5 minutes on a cutting board.

In a small bowl, whisk together mayonnaise, Greek yogurt, garlic, lemon juice, olive oil, and chopped parsley. Adjust seasoning with salt and water for consistency.

Layer sliced grilled chicken on warm flatbread or pita. Drizzle with the creamy garlic sauce and garnish as desired.