01 - Rinse the halal corned beef brisket thoroughly under cold water to remove any excess brine. Place the brisket into a large stockpot or Dutch oven.
02 - Add 4 cups of water, one bay leaf, 1 teaspoon of black peppercorns, 3 whole cloves, 1 teaspoon of mustard seeds, and the small cinnamon stick (if desired) to the pot. Ensure the brisket is mostly submerged; add additional water if necessary to cover.
03 - Bring the liquid to a gentle simmer over medium heat, carefully skimming off any foam that rises to the surface. Reduce the heat to low, cover the pot, and cook the brisket for 2 hours.
04 - Incorporate the peeled and chopped carrots, parsnips, quartered potatoes, chunked rutabaga (or turnip), and quartered onion into the pot. Cover again and continue to simmer for an additional 45 minutes.
05 - Add the cabbage wedges to the pot, cover, and cook for another 20 to 30 minutes, or until both the brisket and all vegetables are fork-tender.
06 - Carefully remove the cooked brisket from the pot and transfer it to a cutting board. Allow it to rest for 10 minutes before slicing against the grain.
07 - Arrange the sliced brisket and cooked vegetables attractively on a serving platter. Ladle a small amount of the simmering broth over the top and garnish with the chopped fresh parsley.
08 - Season the dish to taste with salt and freshly ground black pepper. Serve immediately while hot.