1) Lay out walnuts on a sheet pan and roast them for about 6 minutes at 350 degrees. Watch them closely and turn them once half way through.
2) Combine walnuts, arugula, cheeses, and garlic in a food processor and pulse until it’s a rough paste.
3) Drizzle in olive oil and pulse again.
4) Add pesto to a small pan and add about 1 cup of hot pasta water to the pan. Stir well.
5) Bring to a simmer, stir in cream, and continue to simmer. Season with salt and pepper.
6) When pasta is done, drain it and add it straight to the pesto.
7) Serve with a drizzle of finishing oil and extra grated cheese.