01 - Using a sharp knife, cut deep slashes into the chicken pieces to allow marinade to penetrate deeply into the meat.
02 - In a large bowl, whisk together yogurt, lemon juice, vegetable oil, minced garlic, grated ginger, cumin, coriander, paprika, garam masala, turmeric, chili powder, and salt until smooth and well combined.
03 - Add chicken to the marinade, turning to coat all pieces thoroughly. Cover bowl and refrigerate for at least 4 hours, preferably overnight for maximum flavor absorption.
04 - Preheat oven to 430°F or prepare grill for medium-high heat. Line a baking tray with aluminum foil and place a wire rack on top.
05 - Arrange marinated chicken on the rack, leaving space between pieces. Roast or grill for 30-35 minutes, turning halfway through, until chicken is cooked through and edges are slightly charred.
06 - Transfer chicken to serving platter. Sprinkle with fresh cilantro and arrange lemon wedges and sliced red onion around the edges. Serve immediately while hot.