Preheat oven to 350° F. In a Dutch oven, heat oil over medium heat. Season the short ribs with salt and pepper. Place them in the Dutch oven and sear on all sides. Transfer them to a plate. Set aside.
Add onions and cook for 5 min until translucent. Stir in minced garlic and cook for 30 sec. Stir in the rest of ingredients. Bring to a boil while deglazing the pan. Place the short ribs back into the Dutch oven. Cover with the lid on and place in the oven.
Braise in the oven until the meat is falling off the bone, about 2 hrs. Remove the lid and cook, uncovered, for another 30 min. Remove from the oven. Remove ribs and as much fat from the sauce as possible. Pour sauce on top of meat.