200 g (7 oz) coarsely grated cheese (Red Leicester or Cheddar cheese work well)
salt and pepper
grilled bacon, sausages or a green salad, to serve (optional)
Bring a large pan of lightly salted water to the boil and cook the cauliflower for 7–8 minutes until just tender. Drain well.
Meanwhile, place the flour, butter and mustard powder, if using, in a medium-sized saucepan with the milk. Slowly bring to the boil, stirring constantly, until smooth and thickened. Stir in 100 g (3 1/2 oz) of the cheese and, once it has melted, season to taste.
Tip the cauliflower into a buttered ovenproof dish, pour over the cheesy sauce and sprinkle over the remaining cheese.
Cook under a grill preheated to a medium-hot setting for 3–4 minutes until golden. (Alternatively, if you do not have a grill, cook in a preheated oven, 200˚C/400˚F, Gas Mark 6, for 10–12 minutes, until bubbling and golden.)
Serve with grilled bacon, sausages or plenty of green salad, if desired.