Preheat the oven to 375 °F.
Remove chicken skin and fat and cut it into medium-sized bone-in pieces and place it into a bowl.
Measure other ingredients. Peel the onion and chop it into chunks.
Using a food processor, grind the walnut until smooth paste forms. Then, add onion chunks and process them with walnut paste until smooth consistency forms.
Add walnut onion paste, pomegranate molasses, salt, and pepper to the chicken pieces.
Taste the pomegranate molasses to adjust the sweet-sour flavor to your taste. Add honey or sugar if needed. I like this dish sour.
Using your hand, mix all the ingredients well. You may cover the bowl with a plastic warp and leave it in the fridge for two hours to build more flavor before baking. (optional)
Otherwise, place it in a cast iron skillet, cover it with aluminum foil, and bake it for 90 minutes on the middle oven rack. Halfway through baking, move the chicken around, and if the dish looks watery, you may remove the foil for the other half-time of baking.
Serve it with your favorite side dishes, and enjoy!