Add olive oil to a large dutch oven or stockpot over medium heat. Add onion and garlic to the pot and saute about 5-7 minutes, until onions begin to soften and become translucent.

Add salt, pepper, cauliflower and water or broth to pot. Bring mixture to a boil. Reduce to a simmer, cover and cook until cauliflower is very soft, about 10-15 minutes.

Once cauliflower is soft, use an immersion blender to puree soup to a smooth consistency. If you do not have an immersion blender you can transfer the soup in batches to a blender and blend until smooth. Add more water or broth as needed to reach your desired consistency. Adjust seasoning to taste.

To serve, ladle into bowls and garnish with freshly ground black pepper, parsley and/or chives, and a drizzle of heavy cream (use 1-2 Tablespoons per serving) if desired.