good quality pork or vegetarian sausages, to serve (optional)
Put the potato in a pan of salted water and bring to the boil. Add the cauliflower and boil both vegetables until tender. Meanwhile, heat the milk with the butter, thyme and cheese. When the veg is ready, drain well and blitz in a food processor.
Gradually add the milk mixture (remove the thyme) until you get a smooth, thick purée. Season with salt, pepper and nutmeg. Serve with sausages, if you like.