Make the masala paste: In a small bowl, mix together the onion, garlic, ginger, cinnamon, chili powder, turmeric, cumin, lemon juice, and cayenne pepper (if using).

Marinate the chicken: In a separate bowl, combine the chicken with the Greek yogurt and half of the masala paste. Mix well, cover, and refrigerate while preparing the rice.

Cook the rice: Rinse the basmati rice under cold water and drain thoroughly. In a saucepan, cook the rice according to package directions. Once cooked, fluff the rice with a fork and season with salt and pepper to taste.

Cook the chicken: Heat a nonstick pan over medium-high heat. Add the olive oil and brown the marinated chicken pieces on all sides. Remove the chicken from the pan and set aside.

Finish the chicken tikka masala: Stir in the heavy cream and season with salt and pepper. Let the sauce simmer until thick and creamy. Add chicken broth gradually if the sauce is too thick.

Warm the naan: In a nonstick pan over medium heat, warm the naan on both sides. Cut into wedges for serving.

Serve the chicken over rice and garnish with chopped cilantro. Serve with naan and coconut water.