Kielbasa, Apple, and Onion Strata with Mornay Sauce


In this hearty egg-and-bread casserole, smoky kielbasa, sweet apples, and nutty cheese combine to create a truly unforgettable breakfast dish that’s just right for a weekend. Serve it on its own, or go the extra mile and make a luscious cheese sauce to drizzle on top. And don’t forget the extra touches of honey and salt—they highlight the flavor of the apples and cheese.

Kielbasa, Apple, and Onion Strata with Mornay Sauce
Photo: Yekaterina Boytsova
Active Time:
1 hrs
Total Time:
1 hrs 45 mins
4 to 6


For the Strata

  • 6 large eggs

  • 1 cup whole milk

  • 1 tablespoon Dijon mustard

  • 1 teaspoon kosher salt

  • 1/2 teaspoon freshly grated nutmeg

  • 4 cups cut-up country-style bread (1-inch pieces), left out overnight to dry

  • 1 tablespoon unsalted butter

  • 3/4 pound smoked kielbasa sausage

  • 1 medium onion, diced

  • 2 Granny Smith apples, peeled and cut into 1/2-inch wedges

  • 5 ounces Gouda, cut into 1/4-inch cubes

  • Kosher salt

For the Mornay Sauce

  • 3 tablespoons unsalted butter

  • 4 tablespoons all-purpose flour

  • 1 1/2 cups whole milk

  • Kosher salt

  • Nutmeg

  • 2 ounces grated Gruyère cheese

  • Honey and flaky sea salt, for garnish


  1. Preheat the oven to 350F and lightly butter a 2-quart baking dish or cast-iron skillet.

  2. Whisk the eggs, milk, mustard, salt, and nutmeg together in a large bowl. Using a spatula, carefully fold in the dried bread, allowing it to soak up the majority of the liquid. Set aside for at least 15 minutes.

  3. In a large skillet, melt 1 tablespoon of butter over medium heat. Add the kielbasa and cook, turning once, until browned on both sides, about 3 minutes. Transfer the kielbasa to a cutting board, but keep all of the butter and kielbasa fat in the pan. Reduce the heat to low, add the onions and cook, stirring occasionally until tender but not browned, about 5 minutes. Add the apples and cook until softened, about 3 minutes. Season lightly with salt and allow the mixture to cool a bit. Once the sausage is cooled, slice it into 1/2-inch rounds.

  4. Add the cooled apple mixture, kielbasa, and Gouda to the soaked bread and fold together with a spatula until evenly combined. Transfer to the prepared baking dish or pan and bake until golden brown and a skewer inserted in the center comes out clean, 35 to 45 minutes. (Alternately, let the uncooked mixture rest overnight and bake it the next day straight out of the fridge, adding about 10 minutes to the baking time).

  5. Meanwhile, make the Mornay sauce: In a small saucepan, melt the butter over medium-low heat. Whisk in the flour to make a paste and continue cooking and whisking until golden brown, about 1 minute. Whisk in the milk in a steady stream, continuing to whisk until sauce is smooth. Bring to simmer, reduce the heat to low, and cook, whisking often, until sauce is thick and smooth, about 8 minutes. Mix in the cheese, season with salt and a pinch of nutmeg, and heat until cheese is just melted and sauce is smooth.

  6. Serve wedges of strata topped with Mornay sauce, a drizzle of honey, and a sprinkle of flaky sea salt.

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