In a medium bowl, whisk together Greek yogurt, garam masala, smoked paprika, ground cumin, minced garlic, fresh ginger, and salt until well combined. Add the boneless chicken thighs, ensuring they are thoroughly coated. Cover and refrigerate for at least 1 hour, or for best results, marinate overnight.

Heat 2 tablespoons of oil in a heavy-bottomed skillet over medium-high heat. Add the marinated chicken thighs and sear for about 6-8 minutes on each side. Remove the chicken and set aside.

In the same skillet, lower the heat and add more oil if needed. Add the diced medium onion and sauté for about 5-7 minutes until soft and golden. Stir in the minced garlic, fresh ginger, and a pinch of ground cumin and paprika.

Stir in the tomato puree and allow it to simmer for about 10 minutes until slightly reduced and thickened. Puree the sauce until smooth and return it to the skillet.

Stir in the heavy cream and return the seared chicken thighs to the skillet. Let it simmer on low for 15 minutes.

Remove from heat and sprinkle with chopped cilantro. Serve hot alongside basmati rice or naan.