Make the sauce from scratch and serve with store-bought tortellini for an easy, fresh dinner.
In blender, puree first 3 ingredients with half the spinach and 1/4 cup reserved pasta cooking water, adding more if needed to thin; season sauce. In large saucepan, toss tortellini, sauce, and remaining spinach. Cover and cook over high heat until spinach wilts, about 2 minutes. Toss with 3/4 cup cheese. Season; sprinkle with more cheese.