Why This Recipe Works
For our sole Florentine recipe, we preferred a Parmesan cheese–bound filling to the bread-bound ones we tried. As for the spinach, frozen worked quite well and required no effort outside of defrosting it and squeezing it dry before incorporating it into the filling. With a few sautéed shallots, the simple filling tasted pretty good. As for the sauce, most sole Florentine recipes start with a roux: a combination of butter and flour cooked together until the flour has lost its starchy flavor. To this mixture, dairy—be it milk, cream, or a combination thereof—is added and the sauce is simmered until thickened. For a sauce that could be made the day before and reheated, we substituted cornstarch for flour with great results.