Place cashews in bowl, and cover with hot water. Set aside for at least 30 minutes.
In a large skillet, heat 1 tablespoon olive oil or avocado oil. Add chicken pieces to hot skillet and cook for approximately 4 minutes until chicken is mostly cooked and has turned white.
Add diced onion and garlic. Sauté another 4 minutes until chicken starts to brown and onion is translucent.
Add all sauce ingredients except cashew cream. Add; tomato puree, tomato paste, lemon juice, cardamom, cinnamon stick, bay leaves, ginger paste, garam masala, cumin, salt, turmeric, and fenugreek seeds. Add coconut milk. Stir until well combined.
Cover and simmer about 20 minutes, stirring occasionally to prevent sticking.
remove cinnamon stick and bay leaves.
Drain cashews, and place cashews into blender.
Add about 3/4 cup of water, and blend on high for about 30 seconds or until thick and creamy.
Add cashew cream to the chicken and sauce mixture. Stir until well incorporated. simmer until heated through.
Taste the sauce and adjust the salt as needed.
Garnish with fresh cilantro leaves, green onion, and non-dairy sour cream. Then serve hot with gluten-free naan, steamed rice, or cauliflower rice for a low-carb option.