Spaghetti Aglio e Olio (Garlic, Olive Oil and Chilli)

Salt and Boil the Water. Bring 3 litres of water to the boil with the 30g salt, a fuller 1% since there's no cheese in this dish to help season it. The sauce here is just oil, garlic and pasta water, so well-salted water does much of the seasoning work.

Cook the Spaghetti. Add the spaghetti to the boiling water and cook for 1 minute less than the packet time, stirring during the first minute to stop it sticking together.

Infuse the Oil. Meanwhile, put the olive oil, garlic and chilli into the cold pan and set it over medium-low heat, cooking for 3-4 minutes, stirring, until the garlic is pale gold at the edges and never brown. Starting the garlic in cold oil lets its flavour dissolve gradually into the fat, whereas garlic that browns too quickly turns bitter and acrid.

Add Parsley. Take the pan off the heat and stir in the chopped parsley. Adding it off the heat keeps its colour bright and its flavour fresh rather than cooked and flat.

Reduce the Oil with Water. Reserve 240ml of the pasta water, then carefully add 120ml of it to the garlic oil, standing back as it will spit, and boil hard over high heat for 1-2 minutes until reduced by about half and cloudy. This is where the starchy water begins binding with the oil, the first step toward a sauce that coats the pasta rather than sliding off it.

Drain and Toss the Pasta. Drain the spaghetti and add it straight to the pan, tossing vigorously over high heat for 1-2 minutes, adding splashes of the reserved pasta water as needed, until the oil turns from a slick into a light, creamy coating on every strand. Vigorous tossing emulsifies the starchy water into the oil, the same principle behind a well-whisked vinaigrette.

Finish and Serve. Stir in the lemon juice if using, then serve the spaghetti straight away. A squeeze of lemon lifts the dish with a little brightness without overpowering the garlic and chilli.