Heat a large skillet over medium heat with 1 tbs of oil/butter//ghee. Add half the chicken and cook until browned all over, but not necessarily cooked the whole way through. Remove and set aside. Add another tbs of oil/ghee and the rest of the chicken. Brown the rest of the chicken, remove it, and set it aside.
Turn the heat down to medium-low. Add the remaining oil/butter/ghee to the skillet and melt. Add the garam masala, paprika, coriander, ginger, chili powder, cinnamon stick, and cardamom pods and cook for 1 minute. Add the chicken back into the skillet and stir it around to coat it in spices.
Add the tomato sauce and sweetener. and simmer for 15 minutes. Stir occasionally.
Add the yogurt, heavy cream, and lemon juice. Simmer for 5 more minutes, or until the sauce is thickened and the chicken is cooked through entirely. Add salt to taste and garnish with chopped cilantro.