Heat olive oil in a large skillet over medium high heat. Add garlic and onion, and sauté until onions become translucent, about 2-3 minutes.
Stir in coconut milk, tomato paste, flour, ginger, curry powder, garam masala, chili powder, and salt & pepper until well combined and slightly thickened, about 1-2 minute.
Place chicken into a slow cooker. Cover with sauce mixture. Cover and cook on low heat for 6 hours, or high heat for 3 hours.
Serve garnished with cilantro and greek yogurt.
Video
Notes
Store leftovers in an airtight container in the refrigerator for up to 3 days. Reheat in the microwave or in a large skillet on the stove over medium heat.