Start by dry brining the brisket. Combine 3 tablespoons Kosher salt, black pepper, rosemary, thyme, coriander, and fennel seeds in a small bowl, then season the brisket all over. Place on a sheet pan and refrigerate for 6 hours or overnight. Remove the brisket from the refrigerator 45 minutes before cooking to allow it to come to room temperature.
Heat avocado oil in a 7.25 qt. Doufeu over medium high heat until hot. Add brisket and sear on all sides until browned, about 5-6 minutes per side. Remove the brisket and set aside.
Add onions and garlic, sliced side down, then season with 1 teaspoon Kosher salt, and cook, allowing them to brown for 5-6 minutes, stirring frequently. Add red wine, and cook for 1 minute, scraping up any browned bits on the bottom of the pot. Add pomegranate juice and cinnamon stick, then season with the last teaspoon of Kosher salt.
Nestle brisket, fat side up, into the pot. Add enough beef broth to come ⅔ of the way up the sides of the brisket, about 2 cups. Bring the mixture to a boil, then cover with the Doufeu lid and immediately reduce the heat to low.
Scoop about 2 cups of ice into the top of the Doufeu lid and allow the brisket to cook, covered and undisturbed for 2 hours. There’s no need to replenish the ice – it will gradually melt, and the water will help the condensation collect on the lid of the Doufeu to keep the brisket moist throughout cooking.
After 2 hours, carefully remove the lid without spilling any of the water from the top. Gently flip the brisket and re-cover with the Doufeu lid and let it cook for another 2 hours undisturbed.
After another 2 hours, remove the lid and discard any remaining water in the top. Gently remove brisket from the Doufeu and set aside. Pass the braising liquid through a sieve to remove the solids, then return the liquid back to the pot.
Stir in 3 tablespoons of honey or pomegranate molasses and bring the mixture to a boil. Cook for 10-12 minutes, until the mixture is reduced by half. Combine cornstarch with a few tablespoons of water in a small glass, then pour into the braising liquid. Let it continue cooking until it’s thick enough to coat the back of a spoon, another 2–3 minutes. Remove from heat.
To serve, slice the brisket against the grain and drizzle with the sauce. Top with chopped chives and pomegranate arils.