There are three secrets to cooking good tandoori chicken: using a tandoor clay oven, imparting a rich red color, and using a special yogurt marinade. While a tandoor oven is ideal, a barbecue grill or regular oven can be substituted. The marinade ingredients include lemon juice, garlic, ginger, spices, food coloring, and yogurt. Chicken is marinated for at least a couple hours before being roasted in the oven or grilled, basting occasionally, until just cooked through to avoid becoming dry.