1. Melt 100g of butter in a saucepan.
2. Whisk in 4 tablespoons of plain flour, stirring constantly over a medium heat. This will come together as a solid "paste" called a roux. Keep cooking this for two minutes to cook out the floury taste.
3. Warm 2 cups of a mix of your cooking water and milk or cream, or a combination of all 3. Once warm, start whisking this mix into your roux. The sauce will thicken and should be smooth. If you have a few lumps, strain it through a sieve and return it to the pan.
4. Season well with salt and pepper and add a good handful of grated tasty cheese. Keep stirring, melting the cheese into the sauce.
5. When well combined, pour this over the cauliflower. Top with a bit more grated cheese.
6. Add some breadcrumbs if you like and maybe some diced bacon.
7 Place the dish into the middle of your oven and bake until the sauce is bubbly and a little browned.