Cacio e Pepe (Four Ingredients, No Cream)

Four ingredients, ten minutes, and a reputation for being difficult. Cacio e pepe fails for one reason: heat. Get that right and it is one of the easiest good dinners there is.

Why cheese sauces split

Pecorino is a hard sheep's cheese held together by a protein network with fat trapped inside it. Heat that network past roughly 65C and the proteins tighten and squeeze the fat out, which is exactly what you see when a pan of cheese turns into rubbery strings sitting in a slick of grease.

Every instruction in this recipe exists to keep the cheese below that point. You make the paste with warm water rather than boiling. You take the pan off the heat before the cheese goes anywhere near it. You let the pasta cool for fifteen seconds in the pan if it came straight out of a rolling boil.

Starch does the emulsifying

The other half of the technique is the water. Pasta sheds starch as it cooks, and that starch is what holds fat and water together in a stable sauce - the same job an egg yolk does in mayonnaise.

This is why the recipe calls for less water than you would normally use. Cook 200 g of pasta in five litres and the starch is too dilute to do anything. Cook it in 1.5 litres and the water turns visibly cloudy, almost silky. That cloudy water is the ingredient.

Never rinse the pasta, and always reserve more water than you think you need.

Toasting the pepper

Black pepper is aromatic because of volatile compounds that sit in the oil of the crushed corn. Sixty seconds in a dry pan drives those compounds off the surface and into the air and the pan, and the difference between toasted and untoasted pepper here is not subtle - it is most of what distinguishes the dish from plain buttered pasta.

Crush the corns coarsely rather than grinding them fine. You want occasional bursts of heat, not an even wash of it.

Pecorino, not parmesan

Pecorino Romano is sharper, saltier and more assertive than Parmigiano Reggiano, and it is the traditional cheese. A blend of the two is a common compromise and makes the sauce more forgiving, because parmesan emulsifies slightly more easily. Pre-grated cheese from a tub will not work - it is coated with anti-caking agents that prevent it from dissolving.

Grate it as finely as you can. A microplane produces something closer to powder than to shreds, and it melts into the water almost instantly.

If it splits anyway

Keep tossing and add more hot pasta water, a tablespoon at a time. Most split sauces come back. If it is truly broken, tip the lot into a bowl, add a fresh handful of grated cheese and a splash of water, and stir hard off the heat.

What you are eating

Around 560 calories a serving, with 24 grams of protein and a substantial amount of calcium from the pecorino. It is not a light dish, but it is an honest one - there is no cream anywhere in it, and there never was.