Boil salted water in a large pot. Add pasta and cook according to package instructions (8-10 minutes). Reserve 1 cup of cooking water before draining.

In a food processor, combine arugula, sun-dried tomatoes, cashews, garlic, Parmesan, and salt & pepper. Pulse until coarse.

With the processor running, drizzle in olive oil and a few tablespoons of reserved pasta water until smooth and creamy.

Transfer the drained pasta to a mixing bowl. Combine with pesto, adding reserved water as needed for desired consistency.

Serve hot, garnished with extra Parmesan and a drizzle of olive oil.