Description

This Croissant Strata with Spinach, Feta, and Gruyere is a decadent and savory breakfast casserole perfect for brunch or a special occasion. Layers of buttery croissant cubes are combined with sautéed spinach, sharp Gruyere, and creamy feta, all soaked in a flavorful egg custard with Dijon mustard and warming spices. The strata is assembled the day before, allowing the croissants to absorb the custard for a tender, custardy texture inside and a golden, slightly crisp crust outside when baked. Rich, comforting, and packed with vibrant flavors, this dish serves 8 and is sure to impress your guests.

Ingredients

Scale

Strata Base

3-4 croissants (about 8.5 oz), cut into 2-inch cubes

Custard

10 large eggs
2 cups milk
1 tsp Dijon mustard
1/8 tsp nutmeg
1/2 tsp salt (plus more to taste)
1/4 tsp black pepper (plus more to taste)
1/8 tsp cayenne pepper

Vegetables & Cheese

1 shallot, minced
2 tbsp olive oil or butter, divided
12 oz frozen chopped spinach, thawed and squeezed dry
1 cup Gruyere cheese, shredded
1 cup feta cheese, crumbled

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Instructions

Preheat and toast croissants: Preheat your oven to 350°F (175°C). Spread the croissant cubes on a baking sheet and lightly toast them for 5 minutes to help them hold their shape and develop a slight crunch. Set aside.
Whisk the custard: In a large bowl, combine the eggs, milk, Dijon mustard, nutmeg, salt, black pepper, and cayenne pepper. Whisk thoroughly until the mixture is smooth and well blended. Set aside.
Sauté spinach and shallot: Heat 1 tablespoon of olive oil or butter in a skillet over medium heat. Add the minced shallot and sauté until softened and translucent, about 2-3 minutes. Stir in the thawed, squeezed spinach, season with salt and pepper, and cook for another 2-3 minutes to combine flavors. Remove from heat.
Assemble the strata: Grease a 9×13-inch baking dish with butter or oil. Begin by layering half of the toasted croissant cubes evenly in the dish. Top with half of the cooked spinach mixture, followed by half the shredded Gruyere and half the crumbled feta cheese. Pour half of the egg custard evenly over the layers. Repeat these layers — croissants, spinach, cheeses, and custard — pressing down gently to submerge the bread.
Chill the strata: Cover the assembled dish tightly with foil and refrigerate for at least 2 hours or preferably overnight. This resting time allows the croissants to fully absorb the custard, ensuring a custardy texture when baked.
Bake the strata: Remove the baking dish from the refrigerator and let it rest at room temperature for 30 minutes while you preheat the oven to 350°F (175°C). Bake the strata covered with foil for 30 minutes to allow even cooking. Then uncover and bake for an additional 20 to 30 minutes, until the top is golden brown and the custard is set.
Rest and serve: Let the strata rest for about 5 minutes after baking to firm up. Slice into portions and serve warm as a delightful breakfast or brunch dish.

Notes

For best texture, use day-old croissants or slightly stale to better absorb the custard.
You can substitute fresh spinach for frozen if preferred; be sure to cook and squeeze out excess moisture.
The Dijon mustard and nutmeg add depth of flavor but can be omitted if desired.
Feel free to add herbs like thyme or parsley for extra freshness.
Leftovers can be refrigerated for up to 3 days and reheated gently.
This dish can be made vegetarian by ensuring the cooking fat is butter or olive oil and using cheese suitable for vegetarians.