Place cauliflower in a large pot and cover with water and 1/2 teaspoon salt. Boil until tender. Drain very well.
Place the cauliflower in a large pot, add minced garlic, sour cream and softened butter to the pot, and puree using a handheld blender until thick and smooth.
Serve warm topped with extra butter and chives, if you like.
Notes
Boil cauliflower in salted water to infuse flavor from the start.
For a smooth, creamy texture, use an immersion blender or a food processor/potato masher with extra effort.