Method

• 1.
  For the pesto, place the basil, garlic and cashews in a food processor and process until finely chopped. Add the pecorino and blend again until well combined. Turn the motor off, then gradually pour in the oil, stirring until you have a loose pesto. Season to taste. Transfer to a jar or airtight container, cover with about 1cm extra olive oil, then seal tightly and store in the fridge for up to 5 days.
• 2.
  Bring a large saucepan of salted boiling water to the boil. Add the pasta and cook for 3 minutes, then add the potatoes to the pan and cook for a further 5-8 minutes until the pasta is nearly cooked and the potatoes are just tender. Add the beans and cook for a further 1-2 minutes until the pasta is al dente, the beans are just tender and the potatoes are well cooked.
• 3.
  Drain, reserving about 1/2 cup (125ml) cooking water. Stir 2-3 tablespoons pesto into the pasta, loosening with a little of the reserved cooking water.
• 4.
  Divide the pasta among serving bowls, then serve immediately, topped with extra grated pecorino.