Heat a large pan and sauté butter, onion, and garlic until softened.
Add cauliflower and vegetable stock then bring to a boil.
Simmer for 4 to 6 minutes until the cauliflower is tender.
Cool slightly and blitz the mixture in a food blender to a purée.
Return to the pan, add 200ml of cream, season, and return to a boil.
Simmer for one minute then keep warm.
Heat a deep fat fryer to 190°C.
Boil water and butter in a saucepan for one minute.
Remove from heat, add flour, and beat until smooth and pulling away from sides.
Return to heat for two minutes to cook through.
Remove from heat and beat in eggs one at a time.
Mix in the blue cheese and season with salt and pepper.
Fry teaspoonfuls of batter for 2 to 3 minutes until golden-brown.
Drain on kitchen paper and season with salt.
Ladle soup into bowls, top with choux, and drizzle with vinegar, remaining cream, and oil.