Add enough oil to barely cover the bottom of a medium-sized stock pot (about 2 Tbsp.). Sauté onion and garlic cloves over medium heat until the onions are translucent.
Add the beef stock, chopped beets and lemon juice, bring to a boil and simmer for about one hour, until the beets are very soft.
Stir in fresh dill and season with salt and vinegar, to taste.
Serve with a dollop of sour cream or Greek yogurt (optional).
*Hot and Cold Variations:
(Hot) Beef and cabbage soup: Once the beets are very soft, add shredded cabbage from a small green cabbage, (cooked and chopped) leftover beef brisket, more sugar, salt, and apple cider vinegar (to taste). Bring to a boil and simmer for another 20 minutes. Stir in fresh, chopped dill and adjust for seasoning. Serve with optional sour cream or Greek yogurt, or any dumplings you can find in your freezer.
(Cold) Gazpacho: Puree cooled soup, along with one English cucumber and 2 cups of sour cream (or yogurt), in a Vitamix or high-speed blender until smooth. Add lemon juice if needed. Stir in thinly sliced scallions and chill thoroughly before serving.