The flavors of French onion soup transported into a hearty, cheesy strata. The heart of bread pudding paired with the soul of a classic soup – synergy on a plate.
We’re big fans of bread pudding of almost every stripe. With one basic method and either a savory or a sweet set of ingredients, you can throw together a wide variety of dishes with bread, eggs, and milk: the framework. We generally reserve the term “bread pudding” for a sweet variation, and “strata” for the savory version where there’s usually more eggs involved. It works so well, for the last few years we’ve exclusively used a strata as a Thanksgiving-day stuffing. We liked the technique so much, we wanted to find out what else we could do with it.
Note: This recipe is part of our ongoing series with Serious Eats. You can also find this recipe, and many other great ones on their site.
The sign of an enduring flavor combination is that you can employ it in a multitude of recipes. We love a really well-executed French onion soup: the onions caramelized to sweetness, a gratin of browned bubbly cheese threatening to flow over the top of the soup bowl. It’s often packed with pieces of bread to soak up the flavors anyway, so it doesn’t take a huge leap of imagination to invert the whole concept and create a French onion strata.
We start with the onions – just as in the soup version of French onion soup, the key is to get them as well caramelized as you can – within a reasonable timeframe, that is. We’ve generally allowed a full hour and a half of cooking time for our soup onions to really let the caramelizing process do its work, but we’re not going to put you through that for this recipe. We will ask you to be patient with the onions for 25 minutes, but believe us, it’s worth it. Don’t be afraid to add a little water if need be to prevent the onions sticking to the pan.
We picked up a large soft Italian loaf but any unsliced country-style white bread should work fine. Unlike other bread pudding methods, there’s no need to wait until your bread is fully stale before soaking it in the custard. We started by cutting the bread into cubes, and then dried it in a medium-hot oven for just a short time. The few minutes it’s drying doesn’t give it time to brown, but it does dehydrate it enough to allow it to absorb the egg mixture without getting overly soggy. (If you already have stale bread, you can skip this step, of course.)
There’s also no need to soak your bread overnight. Again, we’re not looking for a complete pudding-like consistency that serves a sweet recipe well; this dish will have a definite texture. We recommend around 15 minutes for the soak, but you could go longer.
Finally, assemble the dish by layering the soaked bread, onions and cheese – make sure you get a couple of layers of each before topping with a little more cheese. Bake to perfect pudding-interior, crunch-topping texture, and enjoy,
And there you have it: French onion soup – without the soup. A versatile dish that will serve you well for a breakfast, lunch or as an evening side. So good, you won’t want to wait for dessert to have pudding.
French Onion Strata
For the Caramelized Onions:
- 3 tablespoons 45g unsalted butter, plus more for greasing baking dish
- 3 large Spanish onions about 2 1/2 pounds; 1kg, thinly sliced
- 1 teaspoon sugar
- 1 teaspoon kosher salt
- 3 medium cloves garlic minced
- 2 teaspoons finely chopped fresh thyme leaves
- 1/4 cup 60ml dry sherry
- 1/2 cup 120ml dry white wine
For the Strata:
- 1 large Italian or French bread loaf about 1 pound; 450g, cut into 1-inch cubes
- 6 large eggs
- 3 1/2 cups 830ml half and half or whole milk
- 1 1/2 tablespoons 22ml smooth Dijon mustard
- 1 tablespoon 15ml Worcestershire sauce
- 1 teaspoon 5ml fish sauce (optional)
- 1/2 teaspoon kosher salt
- 1 teaspoon freshly ground black pepper
- 1 1/2 cups 8 ounces grated Gruyère cheese
- For the Caramelized Onions: In a large skillet, melt butter over medium heat, then add onions, sugar, and 1 teaspoon salt. Cover and cook, stirring every few minutes, until onions have softened, about 10 minutes. Remove lid and cook, stirring frequently and keeping skillet uncovered, until onions are deep golden brown, 20 to 25 minutes; if onions threaten to burn at any point, stir in a tablespoon or two of water as needed, and/or lower heat. Add garlic and thyme and cook 1 minute longer. Add sherry and wine and cook until liquid has almost completely evaporated, about 3 minutes. Remove from heat and set aside.
- Meanwhile, for the Strata: Preheat oven to 350°F (177°C). Spread bread in a single layer on a baking sheet. Bake until bread is dry but not browned, about 8 minutes.
- In a large bowl, whisk together eggs, half and half or milk, mustard, Worcestershire sauce, fish sauce (if using), 1/2 teaspoon salt, and pepper. Add dried bread and let soak in custard for at least 15 minutes and up to 30 minutes.
- Butter a 12-inch cast iron skillet or a 9- by 13-inch baking dish and add half of bread. Scatter half of caramelized onions and half of cheese all over. Layer remaining bread on top and scatter remaining onions and cheese over. Drizzle any remaining custard all over, then bake until bread is crisp and custard is just set, about 35 minutes. Serve hot or at room temperature.