Heat ghee in a large skillet over medium heat; sauté onions until soft and translucent, approximately 8 minutes.
Add garlic and ginger to the skillet; cook for 1 minute until fragrant.
Stir in turmeric, cumin, coriander, and cardamom; toast the spices for 30 seconds while stirring constantly.
Transfer the onion and spice mixture into the slow cooker basin.
Add the chicken pieces, ground almonds, chicken stock, and honey to the slow cooker; stir well to combine.
Cover and cook on 'High' for 3 to 4 hours or 'Low' for 6 to 7 hours until chicken is tender and cooked through.
Thirty minutes before the end of the cooking cycle, whisk together the Greek yogurt and coconut milk in a small bowl, then stir into the slow cooker.
Stir in the garam masala and season with salt and white pepper to taste.
Continue cooking for the remaining 30 minutes to allow the sauce to thicken slightly.
Garnish with fresh cilantro and toasted almond flakes before serving with basmati rice or naan bread.