1. Bring a large saucepan of lightly salted water to a boil. Add the cauliflower and boil for 7 minutes, or until almost tender. Drain, rinse under cold water, and drain well. Arrange the cauliflower in an ovenproof serving dish. Position the broiler rack about 8in (20cm) from the source of heat and preheat.

2. To make the cheese sauce, melt the butter in a medium saucepan over low heat. Whisk in the flour and mustard and cook without browning for 2 minutes. Remove from the heat and whisk in the milk. Return to the heat and bring to a boil over medium heat, whisking often. Reduce the heat to low and simmer until thickened and no flour taste remains, about 2 minutes. Remove the pan from the heat, add ¾ cup of the Cheddar cheese, and whisk until melted. Season with salt and pepper. Pour over the cauliflower.

3. Toss the remaining cheese with the bread crumbs. Sprinkle over the cauliflower. Place the dish under the broiler for 3–5 minutes, or until the sauce bubbles and the crumbs are golden. Serve hot from the dish.

Variation: Herb Cauliflower Cheese

For a crisp, herbed topping, toast the bread crumbs in a little oil until golden. Add a handful of chopped herbs, such as parsley, chives, and thyme. Stir well with the reserved cheese and sprinkle over the sauce and cauliflower just before baking.