In a large skillet over medium-high heat, add the oil. Season the short ribs with salt and pepper. When the oil is hot, brown the short ribs, in batches, until they are browned on all sides, about 3-4 minutes per side.
While the short ribs are browning, place a layer of onion and carrot pieces into the bottom of a slow cooker and season them with salt and pepper. Place the browned meat on top. Add the remaining onions and carrots along with the parsnips and herbs. Add Worcestershire and pour over the stout and add enough water to almost cover the contents. Cover and cook on low for 6-8 hours, or until the meat is very tender.
To serve, carefully remove the meat and vegetables from the slow cooker. Strain the juices. Serve the ribs with the juice and garnish with chopped parsley leaves.
Please keep in mind that nutritional information is a rough estimate and can vary greatly based on products used.