Diana Chan's Roman-style lemon spaghetti. Lemon zest peeled in long strips for perfume, lemon juice in for acidity, cream and butter emulsified together over low heat into a glossy sauce that coats every strand of Barilla No. 5. Parmesan finishes; black pepper insists.

Spaghetti al limone is the simplest of the Roman pasta classics, plainer even than the carbonara or the cacio e pepe. It works only if the lemons are good. Use unwaxed organic lemons if you can find them; the zest is doing the structural work of the sauce and any wax or treatment will throw the flavour off.

The emulsion is the technique. Butter and cream over low heat, pasta water added a splash at a time, the cooked spaghetti tossed through hard with tongs until the starch and the fat bind into a creamy sauce that clings rather than pools. Don't let it boil after the cheese goes in or the parmesan will seize and split.

Five ingredients, twenty minutes, no faking it. Serve immediately in warm bowls with a final shower of parmesan and a generous crack of pepper. A glass of cold Greco di Tufo alongside; bread on the side.