Spinach Basil Pesto

This is my adaptation of a pesto that Ina Garten's makes.

In a food processor, combine ¼ cup each of pine nuts and unsalted walnuts. Add a cup or so of fresh basil leaves, and 2 cups of baby spinach leaves. Zest of half a lemon, a peeled clove of garlic, and ¾ cup grated parmesean cheese and 1 teaspoon of black pepper. Pulse until finely chopped, then drizzle in olive oil while motor is running until pesto is desired consistency. Give it a taste to see if it needs salt. Sometimes the cheese is salty enough. I like my pesto a little on the thick side, so that when I add it to something hot it thins out a bit.
This is the Pesto that I added to my homemade mashed potatoes and it was delicious. The potatoes come out greenish! So fun! Remember to go easy on the salt in your potatoes though because the pesto is already salty.