Trim - cut off the top - and clean the radicchio. Dry it with a kitchen cloth and set it aside.

If needed, unshell the walnuts. Transfer them to a food processor, add the olive oil, and pulse until coarsely chopped.

Cut the parmesan into small pieces and add it to the food processor as well. Add a pinch of salt and a few grinds of pepper (4-6). Pulse for a few seconds to amalgamate.

Add the radicchio and pulse until your desired consistency: crunchy or creamy. The important thing is that the ingredients are well combined. Help yourself with a spatula to press down what sticks to the walls.

Ready! Cook any short or long pasta according to the package directions, and simply season each serving with one to two tablespoons of your Italian radicchio pesto.