Cut the chicken up into bite-sized chunks and generously coat them in the turmeric, ginger, salt, and chili powder. Set aside in a bowl.
Heat a skillet to medium heat and add the butter. As the butter melts dice the onion and garlic and add it to the pan. Cook for 5-10 minutes until the onion is caramelized and becomes a golden brown color.
Increase the pan heat to medium-high and add the chicken. Seal it by cooking on medium for 5- 8 minutes stirring continuously – the outside of the chicken pieces should be white.
Once the chicken looks almost fully cooked add in the yogurt and tomato paste. Using a spatula mix in the tomato paste so it runs smooth through the yogurt. It should be a light brown/orange color at this point, add the mixture to the chicken and onions. Turn the heat to low, add in the chopped cilantro, a squeeze of fresh lemon juice and cook for 35-45 minutes.