1.Preheat oven to 350 degrees.
2.Season all sides of the short ribs with salt and pepper.
3.Heat a heavy, oven-safe pot over high heat. Add in olive oil and allow to heat briefly. Sear short ribs in olive oil, about 1 minute per side. Remove from pot and set aside.
4.Add in onion and saute 2 to 3 minutes. Add in garlic and saute 1 minute more.
5.Pour in beef broth and Worcestershire sauce. Bring to a simmer. Add in meat. Place a rosemary sprig on top.
6.Cover and transfer to preheated oven for about 2.5 hours, until meat is tender.
Note:Don't have an oven safe pot? You can let it simmer, covered, in a regular pot on the stove for 2.5 hours.