If you don't have buttermilk, just squeeze the juice of one lemon into the milk. Stir and let it sit at room temperature for 10mins.

Remove the flowerettes from the cauliflower head. Peel the onions, garlic and carrots then roughly chop into small chunks together with the celery stalk.

Put all ingredients into a small pot and season with salt and pepper. Let it simmer on a medium-low heat until all the vegetables are soft.

Use a hand blender or a food blender until the soup is smooth and creamy.

Pour into small bowls or ramekins and sprinkle with cayenne pepper before serving.