"Khoresh-e Fesenjan is an Iranian stew with chicken, pomegranate syrup and ground walnuts which is perfect for the slow cooker. Depending on how big your chicken is and how sweet you like the sauce, use more or less pomegranate syrup."
Rub chicken pieces with salt and pepper. Heat 1 tablespoon butter in a large deep skillet over medium-high heat and brown chicken in batches from all sides, about 5 minutes per batch. Set aside.
Melt remaining 3 tablespoons butter in the same skillet and saute onion until soft and translucent, about 5 minutes. Add garlic, cinnamon, and cardamom and cook for 3 minutes. Add water and bring to a boil. Cook until liquid starts to thicken, 8 to 10 minutes. Add walnuts and cook everything into a thick paste, about 10 minutes. Add chicken pieces, pomegranate syrup, and honey and mix well. Add to a slow cooker and sprinkle with saffron. Cover with a lid.
Cook on Low until chicken is no longer pink at the bone, about 4 hours. Remove chicken from pot and debone. Shred meat with 2 forks and return to the slow cooker. Cook on High uncovered until sauce thickens, about 30 minutes. Season with salt and pepper. Serve sprinkled with pomegranate seeds.