Use basil and chives if you can, because the basil plays up the sweetness in the peas, and chives work wonders for boiled potatoes. You must pour the vinaigrette on before the potatoes cool and don’t be alarmed if it soaks into the potatoes before you can say mum, it’s supposed to happen that way. Those potatoes will take on the sharp flavor of the wine vinegar, and be better for it. It’s okay that it seems too dry, that’s why you add the butter. The end product — with the butter and everything mashed up a bit — is soft, creamy, and rich, with a background kick. Bring it to your next barbecue. You can even tell everyone it’s healthy, I’ll keep the secret