In a large bowl, combine yogurt, garlic, ginger, cumin, garam masala, paprika, and salt. Add chicken thighs and coat well. Cover and marinate for at least 1 hour, or overnight for best results.

Preheat your air fryer to 400°F (200°C). If using a slow cooker, skip to the next step.

Place marinated chicken in the air fryer basket, ensuring they are not overcrowded. Cook for 15-20 minutes or until crispy and cooked through, turning halfway.

In a large saucepan, melt butter over medium heat. Add tomato purée and simmer for 5 minutes.

Stir in heavy cream and mix well. Add the crispy chicken to the sauce and coat completely. Simmer for an additional 5 minutes.

Garnish with cilantro if desired. Serve hot over rice or with naan.