Lightly coat the bottom of the 4 or 5-quart slow cooker with 2 a bit of vegetable oil and place 2 slices onion along the bottom.
Season the 4 bone-in short ribs with the ¾ teaspoon kosher salt and ¼ teaspoon ground black pepper. In a heavy skillet heat the 2 tablespoons olive oil over medium-high heat. Add the beef and brown on all sides.
Transfer the browned beef to the slow cooker placing on top of the sliced onions.
Add the 2½ cups beef broth, 1 cup water, 6 small red potatoes, 4 carrots, 2 parsnips, 4 cloves garlic and ¾ teaspoon dried thyme. Cover the slow cooker and cook on high for 4 hours.
In a small bowl whisk together the2 tablespoon all-purpose flour and 1 tablespoon butter, melted to make a paste. Uncover and stir in the flour paste. recover and cook for an additional 30 minutes.The stew should now begin to thicken. Check the short ribs have reached an internal temperature of 165°F.
Notes
The parsnips impart a slightly sweet flavor to the stew.
Rutabaga can substituted for potatoes.
Stew can also be cooked on low for 7 hours plus on high for 30 minutes.