Salsa Verde

Rinse the tomatillos well — the husks leave a sticky film that tastes soapy.

Quarter them and put them in a blender with the chillies, onion and garlic.

Pulse in short bursts until coarsely chopped, stopping well before it looks smooth.

Add the coriander, lime juice and salt and pulse two or three more times.

Taste. Tomatillos vary a great deal; add the sugar only if it is puckeringly sharp.

Pour into a bowl and leave for 10 minutes before serving, which lets the raw onion and garlic settle down.

It keeps three days in the fridge and separates as it stands, so stir it before it goes on the table.