Heat a dutch oven (or large soup pot) over medium high heat for 2 minutes. While it is heating up, salt the short ribs generously on all sides. Add the olive oil, and cook the short ribs 3 minutes per side on all sides until golden brown. Do not overcrowd the pan. If necessary, cook the short ribs in batches. Transfer short ribs to the slow cooker after browned, with the meat side down, bone side up.

In the same dutch oven in the remaining oil/fat, add the vegetables and cook for 5-8 minutes, until they begin to soften. Add the tomato paste, cook for 1 more minute. Add the orange zest and orange juice. Scrape the bottom of the pan until there are no more brown bits. Add the chicken stock, balsamic vinegar, cinnamon and bay leaf. Stir to combine. Transfer cooking liquid to the slow cooker. Gently move the short ribs to make sure the cooking liquid gets under the short ribs. Cover and cook on low for at least 8 hours, or high for at least 4 hours.

After the short ribs have cooked, reduce the cooking sauce. Gently remove the short ribs from the slow cooker. They will be very tender, and may fall off the bone. This is OK. I also like to pinch off any large pieces of fat that didn't render off the short ribs using tongs. Discard any fat.

Once all the short ribs are removed, strain the sauce to remove all the vegetables. Discard the cooked vegetables. Transfer the cooking liquid to a fat separator, and allow to sit for 5 minutes. You should have about 4 cups of sauce. Transfer the short ribs back to the slow cooker and cover.

Once the cooking liquid has settled, pour the sauce into a large pot. Discard the fat. (If you don't have a fat separator, transfer the cooking liquid to a large bowl, allow to sit for 5 minutes, then spoon the fat off the top once it has settled.)

Boil the sauce for about 8 minutes, until it has reduced by half, to about 2 cups. Pour the reduced sauce back in the stock pot over the short ribs. Continue to cook over low until ready to serve, about 1 hour.

One hour before serving, bake the sweet potatoes. Preheat your oven to 350 degrees with the rack in the middle. Rub the sweet potatoes with olive oil, and salt the skin generously. Bake on a baking sheet for 1 hour, until very soft.

To serve, split the sweet potatoes in half, and sprinkle the inside with a pinch of salt. Divide the short ribs on top of the sweet potatoes, drizzle with sauce, and garnish with orange zest.