Bring a large saucepan of water to boil, salt well then cook the pasta according to the packets instructions.
Whilst pasta is cooking, put all ingredients except the pasta into a food processor and blitz until thick and nubbly. It may seem a little thick now, but the pasta water will thin it out and make it stick to the pasta.
Before draining the pasta reserve a cup of the cooking water. Add a little of the pasta water to the pesto to make it a little more pliable. Combine pasta and pesto. Using a wooden spoon amalgamate the pesto with the pasta, add more pasta water if necessary so that the pesto coats every strand.
Servings 6