In a large skillet, heat 2 tablespoons of vegetable oil and 2 tablespoons of butter over medium heat until the butter is melted and bubbling. Add 1 finely diced onion and sauté for 3-4 minutes, stirring frequently until golden and translucent. Then, add 1 tablespoon of minced fresh ginger and 2 minced garlic cloves, cooking for an additional 30 seconds until fragrant.

Add 1 pound of boneless, skinless chicken thighs cut into bite-sized pieces to the skillet. Sprinkle with 1 tablespoon of garam masala, 1 teaspoon of chili powder, 1 teaspoon of cumin, and salt and pepper to taste. Stir until the chicken is well-coated in spices and cook for about 5-6 minutes, until the chicken is no longer pink.

Pour in 1 cup of heavy cream and stir well to combine, ensuring that all the chicken pieces are submerged in the creamy mixture. Increase the heat to medium-high and bring the sauce to a gentle simmer. Allow it to cook uncovered for 8-10 minutes, stirring occasionally, until the sauce thickens.

Once thickened, remove the skillet from heat and taste for seasoning, adjusting with more salt or spices if necessary. Serve over fluffy basmati rice or alongside warm naan, garnished with chopped cilantro and an extra tablespoon of butter for extra richness.