Preheat oven to 350°F and toast walnuts for 10 minutes until aromatic.
Sauté onions in oil until golden, then blend with toasted walnuts, spices, 1 cup pomegranate juice, and molasses into a paste.
In the same pot, brown chicken pieces. Add cubed butternut squash and cook briefly.
Add walnut paste and remaining pomegranate juice. Cover and simmer on low for 1.5 hours, stirring occasionally.
Taste and adjust sweet-tart balance with molasses or sugar. Thin with juice if too thick.
Sprinkle with pomegranate arils and toasted walnuts. Serve hot with saffron rice.
