In a large bowl whisk together yogurt, lemon juice, garam masala, turmeric, cumin, paprika, 1 teaspoon salt, and 1/4 teaspoon black pepper until smooth.

Add the chicken cubes to the bowl and stir until all pieces are well coated in the marinade.

Cover the bowl and refrigerate for at least 30 minutes to marinate.

Prepare the onion, garlic, and ginger while the chicken marinates.

Heat a large skillet over medium high heat and add 1 tablespoon of the butter.

Add the marinated chicken with all of the marinade to the hot skillet in an even layer.

Cook the chicken, stirring occasionally, until lightly browned on the outside, about 5 to 7 minutes; the chicken does not need to be fully cooked through.

Transfer the browned chicken and any juices to a plate and set aside.

Reduce the heat to medium and add the remaining 2 tablespoons butter to the same skillet.

Add the chopped onion and cook, stirring often, until soft and lightly golden, about 5 to 8 minutes.

Add the minced garlic and grated ginger and cook, stirring constantly, for 1 to 2 minutes until fragrant.

Pour in the crushed or chopped tomatoes and stir, scraping up any browned bits from the bottom of the skillet.

Bring the tomato mixture to a gentle simmer and cook, stirring occasionally, for about 10 minutes until slightly thickened and deeper in color.

Reduce the heat to medium low and stir in the heavy cream until the sauce is smooth and creamy.

Season the sauce with the remaining 1/4 teaspoon salt and 1/4 teaspoon black pepper, then taste and adjust seasoning with more salt or garam masala if desired.

Return the browned chicken and any accumulated juices to the skillet, stirring to coat the pieces in the sauce.

Simmer the chicken gently in the sauce for 10 minutes, stirring occasionally, until the chicken is cooked through and the sauce has thickened slightly.

Remove the skillet from the heat and let the butter chicken rest for 2 to 3 minutes to settle.

Garnish the top with chopped fresh cilantro.

Serve hot with basmati rice or naan.