Apparently, polenta is the secret casserole base that no one's told you about. The sauce to got with this casserole is inspired by the popular breakfast, egg florentine. It combines Parmesan cheese, garlic, onions and a whole lot of baby spinach. To make this vegetarian polenta florentine, you'll need prepared polenta, baby spinach, unsalted butter, yellow onion, all-purpose flour, and freshly squeezed lemon juice
