An excellent side dish for roast dinners or you could stir in some tinned cannellini bean to make a vegetarian dinner. The magic is in these cheese sauce - so once you've got that down you can add any other veggies to the dish you would like.
Preheat the oven to 220 degrees C. Wash the cauliflower and remove some of the outer leaves, if you like and break into large florets. Place in a large pot, add enough water to cover the thick stalk and boil for 8 to 10 minutes. Don't overcook as this will continue to cook in the oven. Drain.
To make the cheese sauce; melt the butter over a low heat in a small saucepan and add the flour. Use a whisk or wooden spoon to mix them together. The mixture should pull away from the sides of the pot but continue to stir for another minute to allow the flour to cook.
Pour in a little of the milk and whisk or stir continuously. When the mixture has thickened up, add more milk but keep stirring. Continue to do this until the sauce has thickened but is still pourable. Add the grated Parmesan and stir well. Season with salt and plenty of black pepper.
Place the drained cauliflower in an oven proof dish. Pour the cheese sauce over the cauliflower, making sure you cover all of it. Sprinkle over the grated cheddar cheese. Bake in the oven for 20 - 25 minutes or until the cheese has turned golden brown.