The night before or the morning of, heat a large heavy bottom skillet over medium high-heat and add the olive oil. Add the ribs to the skillet and sprinkle with salt, pepper and 2 tablespoons brown sugar. Sear the ribs on all sides for about 1 minute per side. Remove the ribs and place them in the crockpot bowl.
To the bowl add the onion, garlic and carrots. Sprinkle the brown sugar over everything and then add the pomegranate juice, soy sauce, thyme, rosemary, cayenne and parsley. Sprinkle the pomegranate arils over top. Cover and cook for about 8 hours on low (5-6 on high), or until meat is falling off the bone. If you can, rotate short ribs once or twice during cooking. During the last 30 minutes of cooking remove the lid and crank the crockpot to high to let the sauce thicken up a bit.
Meanwhile, make the polenta. Pour the chicken broth and milk into a medium size saucepan and bring to a boil. Lower the heat to medium and slowly whisk in the polenta. Cook, stirring frequently, until the polenta is soft and thick, about 15 to 20 minutes. Keep warm and then just before serving, stir in the mascarpone cheese and butter, season with salt and pepper. If the polenta seems a little thick you can add a tablespoon of butter or extra milk.
Serve the ribs atop a bed of polenta and spoon the sauce overtop the ribs. Garnish with fresh pomegranate seeds.