Ham and Gruyère Croissant Breakfast Bake

A French-inspired brunch strata that gives day-old croissants a second life in a rich egg custard. Layers of ham and nutty Gruyère bake until golden, with Dijon and thyme lending a gentle savory lift.

Serves 6 · 20 min prep · 40 min cook

Estimate for one serving

• 485 cal
• 24g protein
• 28g carbs
• 31g fat
• 2g fiber

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Ingredients

• 5 large (about 14 oz total) day-old croissants
• 8 oz thinly sliced deli ham
• 1 1/2 cups Gruyère cheese, shredded
• 6 large eggs
• 1 1/4 cups whole milk
• 1/2 cup heavy cream
• 1 tbsp Dijon mustard
• 1 tsp fresh thyme leaves
• 3/4 tsp kosher salt
• 1/2 tsp black pepper
• 1 tbsp unsalted butter for greasing

Instructions

1. 1Preheat the oven to 350°F. Generously butter a 9×13-inch baking dish. Tear the croissants into rough 2-inch pieces and scatter half of them evenly in the dish.
2. 2Layer half of the ham slices over the croissants, then sprinkle with half of the shredded Gruyère. Repeat with remaining croissants, ham, and cheese so you have two even layers.
3. 3In a large bowl whisk the eggs, milk, cream, Dijon, thyme, salt, and pepper until fully combined and slightly frothy, about 30 seconds.
4. 4Slowly pour the custard evenly over the croissant layers, pressing down gently with a spatula so the bread begins to absorb the liquid. Let the dish sit at room temperature 15 minutes (or cover and refrigerate overnight).
5. 5If refrigerated, let the bake sit out 20 minutes while the oven preheats. Bake uncovered for 35–40 minutes until the top is deep golden brown, the edges are bubbling, and a knife inserted in the center comes out clean with no liquid egg.
6. 6Remove from the oven and rest 8–10 minutes so the custard sets fully and slices cleanly. The croissants should be crisp on top and custardy underneath.
7. 7Cut into 6 squares, garnish with extra fresh thyme if desired, and serve warm. Leftovers reheat beautifully in a 300°F oven for 10 minutes.