Salsa verde is all about parsley, and from there everyone has their own version. This is mine.
You’ll need 20g flat-leaf parsley, 15g basil, a fat garlic clove (or two small ones), three anchovy fillets, some capers (rinsed if salted, or use cornichons) and the best extra virgin olive oil you can get. Most recipes use red wine vinegar, but I’m partial to white balsamic for its lovely sweet-sour balance.
Pound everything in a pestle and mortar, or pulse it gently, then loosen it with oil. Taste it before seasoning, because the anchovies and capers bring the salt.