Preheat the oven to 180 °C/350F/gas 4.

Peel and dice the celeriac. Trim the feathery top from the fennel and dice, then par-boil both for 6-7 minutes. Remove the vegetables with a slotted spoon and add the broccoli to the boiling water and par-boil for

203 minutes then drain.

Meanwhile, melt the butter in a pan, add the flour and mix well. Add the milk gradually, stirring all the time over a medium heat until the sauce is smooth and glossy.

Keep hot over a gentle heat until the vegetables are ready.

Put the vegetables into a gratin dish and cover with the sauce.

Sprinkle the Parmesan cheese and bread crumbs over the top. Bake for 30 minutes or until the topping is brown and crispy.