Heat oil in a stockpot over medium-high heat. Sprinkle beef with 1/2 teaspoon salt and pepper. Add beef to pan; sauté 10 minutes or until browned. Remove from pan. Add onion, bay leaves, and thyme sprigs to pan. Cover, reduce heat, and cook 10 minutes, stirring occasionally.
Uncover; stir in tomato paste. Increase heat to medium-high. Add carrot, turnips, barley, 4 garlic cloves, and mushrooms; sauté 3 minutes. Add beef, 1/2 teaspoon salt, water, broth, Worcestershire, and beer; bring to a boil. Reduce heat; simmer, covered, for 1 1/2 hours. Discard bay leaves and thyme sprigs.
While stew is simmering, trim beets, leaving root and 1 inch stem on each; scrub with a brush. Place in a medium saucepan, and cover with water; bring to a boil. Cover, reduce heat, and simmer 35 minutes or until tender. Drain; rinse with cold water. Drain; cool. Leave root and 1 inch stem on each beet; rub off skins. Cut each beet into 6 wedges.
Combine parsley, thyme leaves, and 1 garlic clove. Ladle about 2 cups stew into each of 6 bowls. Top each serving with 3 beet wedges, about 1 1/2 teaspoons parsley mixture, and 1 teaspoon horseradish.