Eggs, sugar, heat and a little stamina are all you need to create the foundation of myriad desserts, from ice-creams to mousses.
Egg yolks and sugar. It doesn't get much simpler than that. It's these two ingredients which form what is known as a sabayon. Whisked together to dissolve the sugar and incorporate plenty of air, sabayon is the foundation of many desserts. Think ice-cream, custard, crème pâtissière, semifreddo, génoise sponge, mousses and fruit curds. All of these are based on the simple techniques of whisking eggs and sugar together.
At its most basic, sabayon is just that - a base, or foundation. But add a splash of alcohol and spend some time whisking the mixture over a saucepan of simmering water and you'll find yourself with a foamy, lightly sweet sauce which can transform a simple bowl of fruit into an elegant dessert. Perhaps the most widely recognised version is the Italian zabaglione (sometimes known as zabaione), enriched with a generous glug of Marsala. While its history is somewhat murky (some believe it was invented in the courts of the Medici in 16th-century Florence, others say a fierce Italian warlord fed it to his troops as sustenance, while still others say it was the invention of pastry cooks in Turin), there's no doubt the creation was co-opted some time later by the French, who renamed it sabayon in the process.
The application of heat is important in making a sabayon, although in its earliest forms it was made with raw egg yolks. If the mixture is whisked without heat it's unstable; when heat is applied, albeit indirectly in the form of a bain-marie, it allows the air bubbles to expand and then be sealed, like an envelope, by the egg yolk/sugar/alcohol, giving the mixture structure. It's important the heat is gentle, so the mixture warms to no more than 50 degrees Celsius. Beyond this point you'll have scrambled eggs, a less than desirable result.
Stamina is required when whipping up a sabayon. You want the mixture to be both airy and thick. This may sound counter-intuitive, but when you make it, all will become clear. Use a heatproof bowl (metal is best to conduct the heat quickly) placed snugly over a saucepan of simmering water. Make sure the bowl doesn't hang over the pan too much or you'll find the heat is dispersed unevenly, upping the chances of scrambling. Use a tea towel to hold the bowl still and secure while you whisk vigorously, using a lifting, looping figure-eight motion, all the better to incorporate the greatest amount of air. The mixture will change from a yolky yellow to a pale creamy colour while it doubles, then triples, in volume. You want the mixture to reach ribbon stage, which means that when lifted with a whisk it should sit on top of itself like a ribbon before settling (this will take approximately eight to 10 minutes). At this point it's ready to serve. Alternatively, you can fold a small amount of lightly whipped cream through it, refrigerate it and serve it well-chilled. This further stabilises the sauce.
The choice of booze is yours - any sweet wine or liqueur will work, so let the fruit you're serving it with guide you. The Marsala-spiked zabaglione was traditionally served with the ripest of summer figs, a match made in heaven. Equally well matched are summer berries with moscato or Champagne; amaretto with apricots; or rum with pineapple and mango. We've paired our dessert wine version with lush cherries, and scented it with vanilla bean and a hint of orange (get the recipe here).
So you thought those new-fangled foams were a new idea? What a load of froth and bubble.