Gather the ingredients including beef short ribs, root beer, barbecue sauce, onion, garlic, olive oil, salt, and pepper.
Season the short ribs generously with salt and pepper on all sides.
Heat olive oil in a large Dutch oven or heavy-bottomed pot over medium-high heat. Once hot, add the short ribs in batches and sear them on all sides until deeply browned. This step helps to develop flavor and create a nice crust on the meat.
Remove the seared short ribs from the pot and set them aside. In the same pot, add diced onion and minced garlic. Saute until the onion becomes translucent and the garlic is fragrant, about 2-3 minutes.
Pour in the root beer, using it to deglaze the pot by scraping up any browned bits from the bottom with a wooden spoon. This adds depth of flavor to the sauce.
Stir in the barbecue sauce, coating the onions and garlic evenly. Choose your favorite barbecue sauce, whether it's store-bought or homemade, to customize the flavor of the dish.
Return the seared short ribs to the pot, nestling them into the sauce. Make sure the ribs are submerged as much as possible.
Cover the pot with a lid and reduce the heat to low. Let the short ribs simmer in the sauce for 2-3 hours, or until the meat is tender and falling off the bone. Check occasionally and add more root beer or water if needed to prevent the sauce from drying out.
Once the short ribs are done, remove them from the pot and place them on a serving platter. Spoon the root beer BBQ sauce over the top and garnish with chopped fresh herbs, such as parsley or cilantro, if desired. Serve hot and enjoy!