Heat oil in a large saucepan over medium heat. Add onion and cook, stirring, until beginning to brown, about 4 minutes. Add broth, potato, salt and pepper; bring to a boil. Reduce heat to a simmer, cover and cook until the potato is just tender, about 8 minutes. Add beets and vinegar; return to a boil. Cover and continue cooking until the broth is deep red and the potato is very soft, 2 to 3 minutes more.

Combine sour cream and horseradish in a small bowl. Serve the soup with a dollop of the horseradish sour cream and a sprinkle of parsley.

Tip: How to Prep and Steam Beets: Trim greens (if any) and root end; peel the skin with a vegetable peeler.

Cut beets into 1/2- to 1-inch-thick cubes, wedges or slices.

To steam on the stovetop: Place in a steamer basket over 1 inch of boiling water in a large pot. Cover and steam over high heat until tender, 10 to 15 minutes.

To steam in the microwave: Place in a glass baking dish, add 2 tablespoons water, cover tightly and microwave on High until tender, 8 to 10 minutes. Let stand, covered, for 5 minutes.

No time to prep? Look for Melissa's brand Peeled Baby Red Beets in the produce section of many supermarkets. They're peeled, steamed and ready to eat and contain far less sodium than their canned counterparts.