Step 1

Cut the cauliflower into evenly-sized florets. The size is a little to your choice, but being equal in size helps them cook more evenly. Grate the cheese and set aside until needed.

Step 2

Preheat the oven to 400F/200C.

Step 3

Bring a pot of water to a boil and add some salt. Add the cauliflower and cook for around 3 - 5 minutes, depending on the size of the florets, until the cauliflower is almost cooked. It should be a little resistant to a knife and not too soft.

Step 4

Drain the cauliflower and transfer to a baking dish. You can make a relatively tight single layer or slightly stacked, but don't use a dish that has the pieces too spaced out or the sauce may not cover all properly.

Step 5

Melt the butter in a saucepan over a medium heat and once melted and gently bubbling, add the flour. Stir and cook a minute to make a paste.

Step 6

Gradually add the milk, just a little at a time so that you incorporate each addition and stir out any lumps before adding more. If it thickens too quickly, reduce the heat slightly. Once all of the milk has been added, cook a minute to thicken up slightly, then add the mustard and pepper. Turn off the heat, then mix in around 2/3 of the cheese, reserving some for the top.

Step 7

Drain off any water from the cauliflower in the dish and pour over the sauce to evenly coat the cauliflower. Top with the reserved cheese, forming a layer over the top, then bake for approximately 25 minutes until the top is gently starting to brown.