Instructions

1. For the sauce, melt the butter in a shallow saucepan. When it’s just starting to sizzle, stir in the flour to make a paste. Cook for a minute, then gradually whisk in the milk until you have a smooth, thick sauce. Stir through the mustard, cream cheese, truffle oil (if using) and parmesan, and cook over a low heat until thickened. Season with lots of black pepper.
2. Heat oven to 140C/120C fan/gas. Trim the leaves off the cauliflowers and slice into rough steaks about 1cm thick. Don’t worry about the outside bits not being slices – it will all be used. Assemble the dish a bit like a lasagne. Spoon a quarter of the cheese sauce into a large baking dish and spread it out, then add half of the cauliflower. Repeat the process, finishing with a thick layer of sauce. Scatter over the mozzarella, and the gruyère or cheddar and crispy onions.
3. Bake for 1 hr 30-1 hr 45 mins until the cheese is golden and the cauliflower is soft but not mushy. If you want a golden finish, you can grill it (keep an eye on it) or leave it in when you turn the oven up for the crackling, if making the salt & vinegar roast pork as well. Once baked, leave to stand for 10 mins before serving in the middle of the table.