Frittata

Low heat, and patience

A frittata cooked fast is an omelette that went wrong. The lowest setting on your hob for fifteen minutes is not a suggestion — egg protein sets between roughly 62 and 70°C, and above that it contracts and squeezes out water, which is what makes rubbery eggs weep onto the plate.

You are looking for the edges and most of the centre to be set with a slight wobble in the middle. It will finish setting under the broiler and again in the residual heat after it comes out.

Cook the vegetables first, properly

Twelve minutes on the onion is doing real work: it drives off water and converts starch to sugar, which is where the sweetness in a good frittata comes from. Raw or barely softened vegetables release water into the eggs as they cook and you get a wet, loose set.

This applies to anything watery you add — mushrooms, spinach, courgette all need to be cooked down and, in the case of spinach, actively squeezed.

The parmesan is structural

Cheese in the egg mixture rather than on top. It adds salt, glutamate and fat, and the fat coats the protein strands and interferes slightly with their contraction — which produces a more tender set. It is the same reason a splash of cream is often added, and parmesan does it while contributing flavour.

Serve it warm, not hot

This is how it is actually eaten in Italy, and it is not a compromise. Straight from the pan the texture is loose and the flavours are muted; twenty minutes later it has firmed to sliceable and the vegetables taste of themselves. It is also excellent cold the next day, which makes it one of the more useful things to cook deliberately in advance.

What it is worth nutritionally

19 g of protein and 6 g of carbohydrate a serving, which makes this one of the better low-carbohydrate main courses that does not depend on meat. Eggs carry choline, which most people are short of, and the yolks carry the fat-soluble vitamins — a good argument against the whites-only version.