1 cup freshly grated Parmesan cheese, plus more for topping
3/4 cup toasted pine nuts
1/4 cup extra-virgin olive oil, plus more for topping
1/2 lemon, juiced
1/2 teaspoon salt
Bring a medium pot of water to a boil. To make the asparagus puree, salt the asparagus water and drop the spears into the pot. Cook for 2 or 3 minutes, or until the spears are bright green and barely tender. Drain and transfer to a food processor (preferably) or a blender. Add the spinach, garlic, Parmesan, and the pine nuts. Puree and, with the motor running, drizzle in the olive oil until a paste forms. It should be the loose consistency of a pesto; if too thick, thin it with a bit of the pasta water. Add the lemon juice and salt, then taste and adjust the seasonings.