Season the beef with salt and pepper.
Heat the oil in a non-stick skillet over medium-high heat and sear the beef until it’s browned on all sides, about 5-7 minutes per side.
Transfer the beef into a large slow cooker.
Add the beef broth and wine; stir to incorporate fully.
Add the carrots, garlic, potatoes, onion, tomato paste, mustard, thyme, oregano, sage, barley, bulgur, and bay leaf. Stir to combine.
Cover and cook on high for 4 hours. Turn the heat down to low and cook for 2 more hours, or until the beef is so tender it separates easily when poked with a fork.
Remove bay leaf. Top with sour cream or labneh, if desired, and serve.