Heat the oil in a large pot over medium heat. Add the onion and garlic, and cook until softened, about 5 minutes.
Add the cauliflower, ginger, vegetable broth, salt, pepper, and cayenne pepper. Bring to a boil, then reduce heat and simmer for 15 minutes, or until the cauliflower is tender.
Remove from heat and let cool slightly. Working in batches, puree the soup in a blender until smooth. Return to the pot.
Stir in the cream and yogurt. Heat over low heat until warmed through, about 5 minutes. Serve with a sprinkle of freshly cracked pepper.
Interesting Facts
Cauliflower is a cruciferous vegetable, and is packed with vitamins, minerals, and fiber.
Fresh ginger adds a subtle spiciness to the soup, and has been used in traditional medicine for centuries.
This soup can be kept in the refrigerator for up to 5 days, or frozen for up to 3 months.