2) Heat the olive oil in a large saucepan or soup pot over a medium heat and add the onion and garlic. Cook until softened, but not browned, about five minutes. Add the cauliflower and stock and bring to the boil. Reduce the heat to a simmer, cover and cook until the cauliflower is very soft and falling apart, about 15 minutes.
3) Remove the pan from the heat and, using a handheld blender, puree the soup, or puree in small batches in a blender* and then return it to the pan. Add the grated Parmesan and stir until smooth. Season, to taste, with salt and black pepper. Keep warm until ready to serve.
4) For the Parmesan crisps, line a baking sheet with aluminium foil. Spread the grated cheese over the foil in one even thin layer. Bake for about ten minutes until golden brown and crisp. Remove from oven and allow to cool for five minutes.
5) Break the sheet of crisp cheese into large pieces and garnish each soup bowl with a couple of pieces and a pinch of fresh chives.
*When blending hot liquids, remove the liquid from the heat and allow to cool for at least five minutes. Transfer the liquid to a blender or food processor, filling it no more than halfway. If using a blender, release one corner of the lid before processing. This prevents the vacuum effect that creates heat explosions. Place a towel over the top of the machine, pulse a few times, then process on high speed until smooth.