1. Warm olive oil in a large saucepan over medium heat. Stir in onions and garlic; cook until soft but not browned, about 5 minutes. Stir in beets, and cook for 1 minute.
2. Stir in stock, and season with salt and pepper. Bring to a boil; cover, and simmer until the beets are tender, about 20 to 30 minutes. Remove from heat, and allow to cool slightly.
3. In batches, add soup to a food processor, and pulse until liquefied. Return soup to saucepan, and gently heat through. Ladle into bowls, and garnish with a swirl of cream.