French Onion Soup-Strata
- 20m Prep Time
- 1h 15mCook Time
- 1h Ready In
A savory bread pudding that transforms classic French onion soup into a cozy casserole. Caramelized onions, Gruyère cheese, and sourdough bread are baked in a custard for a satisfying meal.
Ingredients
- 6 large eggs
- 1 1/2 cup whole milk
- 2 tbsp Dijon mustard
- 1 tbsp Worcestershire sauce
- Kosher salt
- freshly ground black pepper
- 1 day-old sourdough bread loaf cut into 1-inch cubes
- 3 tbsp unsalted butter
- 2 large sweet onions thinly sliced
- 4 medium cloves garlic minced
- 1 tsp chopped fresh thyme
- 1/4 cup dry sherry
- 1/2 cup dry white wine
- 2 cup shredded Gruyère cheese divided
Nutrition (per serving, estimated)
Estimated based off 10 of 14 identified ingredients (per 100 g food data, scaled by amount).
Vitamins & minerals
- Calcium: 549 mg
- Iron: 3.27 mg
- Magnesium: 60.6 mg
- Phosphorus: 580 mg
- Potassium: 656 mg
- Zinc: 3.1 mg
Let's Prepare
Collect
Gather these ingredients — no prep needed yet.
- 6 large eggs
- 1 1/2 cup whole milk
- 2 tbsp Dijon mustard
- 1 tbsp Worcestershire sauce
- Kosher salt
- freshly ground black pepper
- 3 tbsp unsalted butter
- 1 tsp chopped fresh thyme
- 1/4 cup dry sherry
- 1/2 cup dry white wine
Prepare
- 1 day-old sourdough bread loaf, cut into 1-inch cubes
- 2 large sweet onions, thinly sliced
- Mince 4 medium cloves garlic
- 2 cup shredded Gruyère cheese, divided
Let's Cook
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Step 1.
Preheat the oven to 350°F.
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Step 2.
In a large bowl, whisk together 6 large eggs, 1½ cups whole milk, 2 tablespoons Dijon mustard, and 1 tablespoon Worcestershire sauce. Season with salt and pepper to taste. Fold in the sourdough bread cubes (about 1 pound, cut into 1-inch cubes) and let them soak, gently stirring occasionally, while you prepare the onions.
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Step 3.
Melt 3 tablespoons unsalted butter in a 10-inch oven-safe skillet over medium-low heat. Add 2 thinly sliced large sweet onions and cook, stirring often, until deep golden brown, about 25 minutes. Stir in 4 minced medium cloves garlic and 1 teaspoon chopped fresh thyme (or ¼ teaspoon dried) and cook until fragrant, about 1 minute. Season with salt and pepper. Increase heat to medium, add ¼ cup dry sherry and ½ cup dry white wine, and cook until the liquid has almost evaporated, about 4 minutes.
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Step 4.
Transfer the onion mixture from the skillet to a large plate or bowl. Rub the skillet with additional butter.
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Step 5.
Add half of the soaked bread to the skillet and top with half of the onions and half of the shredded Gruyère cheese (about 3 ounces). Layer the remaining bread on top and drizzle with any remaining egg mixture. Scatter with the remaining onions and cheese.
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Step 6.
Transfer the skillet to the oven and bake until the bread is crisp and the custard is just set, 40 to 50 minutes. Let cool for 10 minutes before serving.