Cut the chicken into roughly 1-inch cubes. Set them to the side.
In a large bowl whisk together the yogurt, lemon juice, minced ginger, minced garlic, turmeric, Kashmiri powder, garam masala, fenugreek, salt, and pepper until combined.
Thoroughly mix in the chicken. Cover it and place it in the refrigerator to marinate from 30 minutes to 24 hours.
Add 3 tablespoons of ghee to a large rondeau over medium heat. Once melted, add onions, gently season with salt, and sauté for 5 minutes or until lightly browned.
Turn the heat down to low and stir occasionally for 10 minutes or until dark brown.
Stir in the 1 tablespoons each of minced ginger and garlic and cook it just until it’s fragrant, which takes about 30 to 45 seconds.
Sauté in the pepper for 1 to 2 minutes and then mix in the ½ teaspoon of garam masala and 2 teaspoons of Kashmiri powder.
Pour in the tomato puree and cook over medium heat for 5 to 7 minutes or until reduced slightly.
Add in 1 cup of chicken stock and cook for a further 8 to 10 minutes to reduce and concentrate the flavor.
Finish the sauce with 2/3 cup of heavy whipping cream, fenugreek, salt, and pepper. Set it to the side.
In a large carbon-steel or non-stick frying pan over high heat, add in 3 tablespoons of ghee or oil and heat until it begins to smoke lightly.
Place in the chicken and immediately spread it around the pan to get a single layer and let it sit untouched for 3 minutes. Sauté the chicken for an additional 5 minutes or just until the chicken is cooked through.
Transfer the chicken over to the pot with the tikka masala sauce with ¼ cup minced cilantro and stir to combine.
Serve the chicken tikka masala with basmati rice and naan.