Remove the wild fennel and parsley “leaves” from the stems, then wash them and dry them well with kitchen paper. First use a knife to chop them coarsely with the other ingredients (except the olive oil), then blend everything in the food processor (1). Now transfer the pesto you’ve made into a bowl and add the olive oil, a little at a time, stirring very slowly to amalgamate everything well, until you obtain a smooth, creamy sauce.
When you use it to dress pasta, it’s important that you don’t strain the pasta too much and set aside a few spoonfuls of the water it was cooked in, to add if it should seem too dry.
(1) Nowadays we often rely on food processors or blenders, but real pesto is made using a marble or wood mortar and pestle. Here is exactly how it’s done: you start by “pestare” (= crushing) the wild fennel and parsley leaves with the garlic. You crush and grind them until the ingredients are reduced to a pulp. Then you add the pine nuts, chopped sun-dried tomatoes, capers and salt, and continue crushing as you gradually add the olive oil, amalgamating it with the rest of the mixture.