• Heat a spoonful of butter in a pan.
• Once it’s melted and just sizzling, add about a spoonful of white flour, and stir until you have a smooth paste.
• Cook the roux until it’s slightly darker to give the sauce a richer flavour.
• Add a spoonful of milk and stir until smooth. This is the critical step, but it works out fine unless you let it burn.
• Keep adding milk, a spoonful or two at a time, and mixing, until the sauce is quite liquid and you’re not having to stir much.
• Add the rest of the milk a little faster, still stiring.
• Cook until the sauce is heated through, and bubbling.
• Add unhealthy amounts of your prefered cheese, grated, and keep stiring.
• Cook until the sauce starts to thicken and remove from the heat. It’ll thicken more as it cools.

It seems like a lot of steps, but once you get the hang of it, it’s quick and reliable. The recipies that add flour to a lot if liquid have a tendency to get lumpy, this one cooks the flour in fat first and adds liquid slowly, which pretty much eliminates the issue.