In a large saucepan bring water to the boil, add the cauliflower and cook for 4-5 minutes.

When done drain well the cauliflower and then tip into an ovenproof dish.

Preheat the oven to 200c/gas mark 7.

To make the white sauce, melt the butter in a saucepan.

Add the flour and cook on low for approximately 1 minute. Stir constantly.

Gradually add in the hot milk, continuing to whisk until the sauce has thicken.

Stir in, if using, the dijon mustard, 2/3's of the cheese, salt and pepper. Note: If the sauce is too thick stir in a small spalsh of hot milk until the sauce has reached the right consistency.

Pour the sauce over the cauliflower.

Then sprinkle with the remainder of the cheese and, if using, breadcrumbs.

Transfer to the hot oven and bake for 20-30 minutes. It should have a nice golden brown topping when done.