Preheat the oven to 350 degrees F. Heat about 2-tablespoons of the olive oil in a large Dutch oven over high heat.
Season the short ribs well with salt and pepper. Over medium heat, brown ribs for 6 minutes on each side. You will need to do this in batches. Remove the browned short ribs to a plate and repeat with remaining ribs and oil.
Add onion, carrots, garlic, celery, and salt and pepper to the Dutch oven and saute until softened, about 5 minutes. Add the tomato paste and wine to the vegetables and cook, stirring, about 1 minute. Add the stock, diced tomatoes, thyme, and bay leaf. Return the browned short ribs and any juices that have accumulated back into the Dutch oven. Add orange zest. Cover with a heavy lid and place in the oven and braise for 3 hours or until the meat is very tender.
Once the ribs are tender, remove the ribs to a platter. Taste for seasoning. Add salt and pepper, to taste. Serve the short ribs over the stone ground grits, if desired. Garnish with fresh chopped parsley.