Sauce Maltaise — Blood Orange Hollandaise

Maltaise is hollandaise finished with the juice and finely grated zest of blood oranges — a seasonal sauce available only in the short weeks when Maltese and Sicilian blood oranges reach their peak of colour and flavour, typically January through March. It is the classical accompaniment to steamed asparagus, and the combination of green spears, golden sauce, and crimson-streaked orange is one of the most beautiful plates in the French repertoire. Prepare a hollandaise by the standard method: egg yolks whisked with a splash of cold water over gentle heat until thick and pale, clarified butter added in a thin stream until the emulsion is stable. Season with salt and a squeeze of regular lemon juice. This is the base. Separately, juice 2-3 blood oranges and reduce the juice by half in a small saucepan. This concentrates the flavour and colour while removing water that would thin the emulsion. Let the reduction cool to warm. Fold into the hollandaise: 2 tablespoons of the reduced juice and 1 teaspoon of finely grated blood orange zest. Fold gently — the emulsion is alive and can break. The zest is as important as the juice. Blood orange zest contains limonene and linalool, aromatic terpenes that provide the floral, almost perfumed top note that distinguishes Maltaise from mere orange-flavoured hollandaise. Regular orange zest does not contain the anthocyanin pigments responsible for the blood orange's ruby colour, nor does it carry the berry-like undertones of the Moro or Tarocco varieties. The finished Maltaise should be pale gold streaked with ruby — the blood orange should be visible as colour but not as a separated layer. It should taste of butter first, then orange as a bright, almost berry-like high note, with the lemon from the hollandaise base providing background acidity. When it lands on a spear of asparagus, the heat of the sauce releases the zest oils and the plate fills with perfume. Never make Maltaise with regular oranges and food colouring. The flavour profile of blood oranges — berry-citrus with anthocyanin bitterness — is unique and irreplaceable.