How to Make It
In a medium saucepan, combine 2 cups of water with the vinegar and pomegranate syrup and bring to a boil over moderately high heat. Remove from the heat and add the allspice, cloves, bay leaves, cinnamon stick and coriander seeds and let stand for 1 hour. Set a fine sieve over a medium bowl and strain the vinegar mixture. Discard the solids.
Bring a large pot of water to a boil, add the cabbage and cook over moderately high heat for 20 minutes, until just tender. Drain and return to the pot. Pour the vinegar mixture over the cabbage and toss to coat. Cover the pot with a lid and let the cabbage marinate at room temperature for 2 hours.
Place the pot with the cabbage over moderately high heat and add the duck fat. Bring to a boil. Cover the surface of the cabbage with a round of parchment paper and cook over low heat until the cabbage is very soft, 1 1/2 hours. Transfer to a bowl, season with salt and pepper and serve.