Using a bit of emulsion science, the sodium citrate in this recipe enables you to make a smooth sauce that has all the flavour of the cheese that went into it - much more so than a traditional white sauce, and without any greasiness. Although cheese lovers might be tempted to boost the sauce-to-pasta ratio, keep in mind that the sauce is very rich. A little goes a long way.
In a saucepan combine the milk (or water) with the sodium citrate, whisk to dissolve and bring to a simmer over a medium heat.
Gradually add the grated cheese, blending after each addition with a stick blender until melted and completely smooth.
Stir the warm cheese sauce into the pasta and season to taste with salt.