This hearty, homey take on French onion soup celebrates Georgia-grown Vidalia onions, which typically come into season in late April. Naturally sweet Vidalias are perfect for caramelizing, and this indulgent casserole with layers of bread, onions, and cheese is a terrific way to enjoy them. We didn’t think French onion soup could get any more comforting, but we took the Southern route and made it into an even cozier casserole. This dish amplifies the richness of the classic soup you crave, and it’s ideal to serve as a hearty family dinner or pack up and bring to the church potluck. It takes time to slice and caramelize the onions, but you can do this step a day ahead and store the cooked onions in the refrigerator.