How to Make It
Place flour in a shallow dish. Sprinkle beef evenly with salt and pepper; dredge in flour. Heat a large skillet over medium-high heat. Add oil to pan; swirl to coat. Add beef; sauté 10 minutes, turning to brown on all sides. Place turnip greens in a 6-quart electric slow cooker; top with parsnips, potatoes, and onions. Transfer beef to slow cooker. Add tomato paste to skillet; cook 30 seconds, stirring constantly. Stir in wine and broth; bring to a boil, scraping pan to loosen browned bits. Cook 1 minute, stirring constantly. Pour broth mixture into slow cooker.
Place peppercorns and next 4 ingredients (through parsley) on a double layer of cheesecloth. Gather edges of cheesecloth together; secure with twine. Add cheesecloth bundle to slow cooker. Cover and cook on LOW 8 hours or until beef and vegetables are tender. Discard cheesecloth bundle. Remove roast from slow cooker; slice. Serve with vegetable mixture and cooking liquid. Garnish with thyme sprigs, if desired.