• Toast the walnuts in a dry skillet over medium heat until lightly browned. Allow to cool.
• Bring a large pot of water to a boil. (You can use this water to cook pasta, if using, after you blanch the greens.) Blanch arugula for 10 seconds. Using a spider or large slotted spoon, transfer the arugula to an ice bath. Let cool. Remove the arugula from the ice bath and squeeze excess water from the leaves.
• Put the arugula, basil, Parmigiano, Pecorino, walnuts, lemon zest and garlic in a food processor. Pulse to blend. With the machine running, slowly add in the olive oil. Process until smooth. Transfer to a bowl. Season to taste with salt and pepper.
