In a medium-sized bowl, add chicken, yogurt, salt, garam masala, and garlic powder. Stir to completely coat chicken. Cover and let marinate in the refrigerator for at least 1 hour.
Heat a large skillet over medium-high heat. Add oil. Cook chicken for 4 minutes per side. Remove chicken and set aside.
Chicken Tikka Masala Sauce:
In the same skillet, add butter over medium heat. Add diced onion and cook for 6-7 minutes or until it starts to soften. Stir in pepper and cook for 1 minute. Add ginger, garam masala, paprika, garlic powder, turmeric, coriander, and salt. Stir to coat onions. Add brown sugar and tomatoes.
Let simmer for 10-15 minutes or until sauce begins to thicken. Stir in the heavy cream. Add chicken back into the sauce and let cook for an additional 8-10 minutes, stirring often. Add water, if needed.
Serve with basmati rice and naan bread. Top with cilantro.
Notes
*Coriander is cilantro. If using fresh cilantro, finely dice 1 1/2 Tablespoons of fresh cilantro and add to the sauce.*This recipe may be made in the slow-cooker. Add all ingredients (except oil) and cook for 6-7 hours on low or until chicken is tender.