In the past few years, Americans have been treated to a dazzling array of new convenience food; the supermarket aisles are lined with items you can eat right now! I’m not a big fan of most of these. But I am a big fan of pre-washed, pretrimmed greens, like the bags of baby spinach that are almost universally available. Cleaning fresh spinach is no treat: The bunches are filled with sand and grit, requiring multiple changes of water to remove; and it’s time-consuming to separate the fibrous stalks from the tender leaves. But these bags of baby spinach, on the other hand, are ready to go: Tear open the bag, dump the greens into a salad bowl, and they’re ready to dress. Or just toss into the sauté pan with a little olive oil and garlic, and you can be eating bright, fresh spinach in mere seconds. Or throw into the blender with some other ingredients—and bingo! Pesto!
In the Bowl of a food processor, combine the spinach, pine nuts, lemon zest, and lemon juice. With the machine running, gradually add the oil, blending until the mixture is creamy. Transfer the pesto to a medium bowl. Stir in the Parmesan and ½ teaspoon each of salt and pepper. Season the pesto with more salt and pepper to taste. (The pesto can be made 2 days ahead. Cover and refrigerate.)