Maltese Sauce

Sauce Maltaise (Hollandaise brightened with blood orange) teaches the last and most delicate act of sauce-making: how to season an emulsion without breaking it. The one true thing is temperature. Blood orange juice and the sauce must both be tepid; cold juice shocks the butter, high heat cooks the yolks, and either can turn gloss to grease.

The source formula assumed a saucier beside a bain-marie, the warm-water bath, with finished Hollandaise Sauce (No. 30) ready and the oranges added at the instant of service. One cook needs a warm bowl over barely warm water and the citrus prepared before the asparagus is done. The tammy work belongs to the finished Hollandaise and isn't repeated here; that is brigade scaffolding. The orange juice and zest added at the last moment are the dish, so they stay exactly where the formula puts them.

Four blood oranges keep the book's proportion for this roughly two-quart batch, and the coffeespoon measure becomes a level half-teaspoon of zest so a home cook can repeat it. Whisk the juice in slowly, one addition at a time. That is the step that matters; if the emulsion falters, stop before adding another drop, because ça se rattrape.