Place parmesan into Thermomis bowl and mill 10 sec/speed 10. Remove from bowl and set aside
Place butter and leek into Thermomix bowl and chop 5 sec/speed 5. Scrape down sides of bowl and sauté 5 min/Varoma/speed 2.
Add cauliflower and stock and cook 15 min/100°C/speed 2.
Add cream and parmesan and puree carefully 1 min/speed 8. Taste and adjust seasoning.
Serve immediately garnished with chives and cheese on toast!