Chop the onion and cut the chicken thighs into bite-size pieces.
Heat 2 tablespoons of coconut oil in a large skillet over medium heat. Add the chicken and cook for 2–3 minutes per side, just until lightly browned. The chicken does not need to be cooked through.
Add the remaining coconut oil, onion and garlic. Sauté for 2–3 minutes, until the onion begins to soften.
In a medium bowl, whisk together the garam masala, coconut sugar, ground ginger, tapioca starch and sea salt.
Add the coconut cream, coconut or almond milk and tomato sauce. Whisk until smooth and well combined.
Transfer the chicken, onion and garlic to the slow cooker. Pour the sauce over the chicken and stir to combine.
Cover and cook until the chicken is tender and reaches an internal temperature of 165°F.
Stir the sauce well before serving. Serve over rice with your favorite vegetable.