Heat 1 teaspoon oil in a Dutch oven over medium-high heat. Add half of beef; cook 4 minutes, browning on all sides. Remove beef from pan; set aside. Repeat procedure with remaining 1 teaspoon oil and remaining beef. Add onion to pan, and sauté 2 minutes.
Add beef, beets, reserved juice, potatoes, and next 4 ingredients to pan. Bring to a boil, reduce heat, and simmer 45 minutes or until beef is tender. Ladle soup into individual bowls; top with sour cream.