Heat 4-5 tablespoons of the oil in a pan, add onion and cook for a few minutes until just golden. Add potatoes, cook 2 minutes more and add water. and milk. Crumble in the stock cubes and simmer stock until potatoes are tender. Place aside to cool.
Melt the butter and remaining oil deep saucepan, add the crushed garlic, parsley and cauliflower florets. Cook over medium heat for 2 minutes, add salt and pepper to taste, moisten with 3 tablespoons of the hot stock and reduce the heat.
Put potato mix into a blender or food processor and blend, when processed return to the rinsed out saucepan and add the caulifower mixture and leave for a few minutes for the flavours to blend.
Serve hot topped with parmesan cheese and parsely.