We're big fans of bread pudding of almost every stripe. With one basic method and either a savory or a sweet set of flavorings, you can throw together a wide variety of dishes with a basic framework of bread, eggs, and milk. We generally reserve the term "bread pudding" for a sweet variation and "strata" for the savory version, which usually involves more eggs. It works so well that for the last few years, we've made a strata for Thanksgiving instead of stuffing.
As for flavorings, we love the same components you'll find in a really well-executed French onion soup: onions caramelized until they're nicely sweet; a gratin of browned, bubbly cheese threatening to flow over the top of the bowl. The soup is often packed with pieces of bread to soak up the flavors anyway, so it doesn't take a huge leap of the imagination to invert the ratio and create a French onion strata.
We start with the onions—just as in the soup version, the key is to get them as well caramelized as you can. Of course, that can mean slowly cooking the onions for upwards of an hour. Since we wanted this strata to be a more convenient dinnertime option, here we trim the time to about 25 minutes, adding sugar to help speed things along; the onions won't be quite as deeply dark this way, but they'll still be pretty amazing. (Mind you, if you want to go through the more time-consuming process of a long, slow caramelization, feel free to do so.) No matter what, don't be afraid to add a little water at any point if necessary to keep the onions from burning.
For the bread, we picked up a large, soft Italian loaf, but any unsliced country-style white bread should work fine. There's no need for stale bread, but it does need to be dried in a low oven at least a little—that will help it absorb the egg mixture without becoming a sopping-wet mess.
There's also no need to soak your bread overnight. Again, we're not looking for a completely pudding-like consistency, which would be better suited for a sweet recipe; the goal here is more a contrast of textures, with some crispy bits and some soft, creamy ones. We recommend around 15 minutes for the soak, but you could go longer.
Finally, assemble the dish by creating alternating layers of soaked bread, onions, and cheese, then bake it just until the eggs are set.
And there you have it: French onion soup, without the soup. A versatile dish that will serve you well for breakfast, lunch, or even a light, one-baking-dish dinner. Plus, you won't have to wait for dessert to have your pudding.