Cook the pasta in a pot of boiling salted water according to the manufacturer’s instructions. Use tongs to transfer the pasta to a large bowl.
While the pasta is cooking mince the garlic in a food processor or blender. Halve the avocado, pit it and scoop out the flesh into the food processor. Add the arugula, lemon juice, olive oil, salt and pepper and puree into a sauce.
Stir the avocado sauce into the pasta. Top with fresh herbs before serving.