Small Win #42: A sauce worth understanding

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There is a sauce in Italian cooking that deserves to be everywhere but isn’t.

You may know it from vitello tonnato — a Piedmontese classic of sliced veal blanketed in a creamy, anchovy-spiked tuna sauce — but the vitello is a distraction, if you ask me, because: the sauce! The sauce is the thing.

Silky, savoury, deeply flavoured and deceptively light, a tonnato sauces tastes like it takes considerably longer to make than it does. It tastes deeper than it should (that’ll be the umami of the anchovies and canned tuna). It is also, at its core, a lesson in one of the most fundamental techniques in cooking: emulsification.

Emulsions are the key to silkiness and satisfaction in cooking, and once you understand how they work, how to bolster their success and how to rescue them when they go wrong, cooking will feel much less perilous: pan sauces and cake batters that don’t split, carbonara and cacio e pepe without fear, dressings that properly cling, the silkiest soups imaginable. Plus, today: an everyday use for tonnato sauce, in a twist on the Niçoise salad.

Love,
Alexina

Coming up — Better tzatziki (plus salted cucumber gimlets); my favourite use for pistachios; a very delicious lunch; the best syrups aren’t cooked.

Oil and water don’t mix — this is not news! But in cooking, we force them to anyway, and the result is something neither liquid could produce alone: a sauce that is simultaneously rich and light.

An emulsion is what happens when one liquid is suspended in tiny droplets throughout another liquid that it would normally repel: mayonnaise is oil suspended in egg yolk, a vinaigrette is vinegar suspended in oil.

Not all emulsions are forever: they can be temporary (e.g. a basic olive oil and lemon vinaigrette, which will split back into layers after a few minutes), permanent (e.g. mayonnaise) or something in between (e.g. hollandaise).

To create an emulsion you need FORCE first and foremost (from a whisk, a food processor, a blender) — but to stabilise an emulsion you need an EMULSIFIER.

Here’s the equation:

FAT + WATER ( + EMULSIFIER ) x MECHANICAL FORCE

Let’s break down the different elements.

Fat

The main ingredient being incorporated: the olive oil in a vinaigrette, the butter in a hollandaise, the oil in a mayonnaise and so on. Add it slowly, especially at the start, but once the emulsion has visibly taken hold, you can add it more confidently.

The form that the fat takes matters.