Peel, cut the onion in half, and then slice into half-moon shapes about 5-6mm (¼") thick.
Heat a medium (20cm or 8") saucepan over a medium heat and add the flour, and cook until it just begins to change colour, 3-5 minutes.
Add the ground walnuts to the pan, stir and then cook for 10 minutes, stirring occasionally to ensure that they do not burn.
Pour the water over the walnuts, stir to form a smooth paste and bring to a gentle boil.
Add a lid, turn down the heat to low, and cook for an hour. You should see the oils from the walnuts rise to the surface. Again, make sure that the walnuts do not burn!
Heat a 30cm or 12" frying pan over a medium-high heat, and when hot, add the oil. Fry the onions until they soften and begin to turn golden, approximately 10 minutes.
Season the chicken generously with half of the salt and all of the pepper
Turn up the heat on the onions, add the chicken and get a nice colour on all sides.
Once the chicken is nice and golden, remove it from the heat and set it aside.
Add the pomegranate molasses and sugar to the cooked walnuts and stir until fully incorporated.
Drop the chicken, onions and remaining salt into the walnuts, cover and then cook on a low heat for 1 hour.Stir every so often to prevent the walnuts at the bottom of the pan from burning. It is vital that you keep the heat low!