Rich with cheese, crusty bread and an eggy custard, stratas can easily serve a crowd. These savory bread puddings are exceptionally versatile and can include a variety of vegetables and meats, such as the spinach and ham featured here. To streamline prep, we call for thawed frozen spinach; be sure to squeeze it dry so the strata won’t become soggy. This is a great do-ahead dish. Assemble the strata, cover with foil and refrigerate overnight. The next day, the foil-covered strata can go directly from the refrigerator to the oven. Bake for 1 hour, then uncover and bake for about another 20 minutes.