In a large bowl, combine plain yogurt, lemon juice, ginger-garlic paste, garam masala, turmeric powder, chili powder, cumin, coriander, and salt. Whisk until smooth. Add the boneless, skinless chicken thighs, ensuring they are thoroughly coated in the marinade. Cover the bowl and refrigerate for 30 minutes to 4 hours.

In a large skillet, heat 2 tablespoons of olive oil or ghee over medium heat. Once hot, add diced onion and sauté for about 5 minutes until it becomes translucent. Toss in minced garlic and ginger, cooking for an additional 1-2 minutes.

Stir in the pumpkin puree and diced tomatoes, mixing well. Pour in heavy cream and chicken broth, followed by a pat of butter. Add smoked paprika, cinnamon, and nutmeg to taste. Bring the mixture to a simmer and let it cook for 15–20 minutes.

While the sauce simmers, heat a little olive oil in another skillet. Add the marinated chicken pieces and cook for 5–7 minutes per side until browned and cooked through, reaching an internal temperature of 165°F (74°C).

Once the chicken is cooked, carefully stir it into the simmering pumpkin sauce, allowing it to meld for another 5–10 minutes. Serve hot over basmati rice and garnish with freshly chopped cilantro.