Description

This Rich Ham and Cheese Croissant Breakfast Bake is a decadent and savory dish perfect for brunch or a special breakfast. Made with day-old croissants soaked in a creamy custard of half and half and eggs, layered with sliced ham, melted Gruyere cheese, and fresh herbs like sage and thyme, this bake is flavorful and comforting. The addition of caramelized onions and Dijon mustard adds depth, while optional garnishes like minced chives and hollandaise sauce elevate it to a luxurious morning treat.

Ingredients

Scale

Croissant and Meat

10 large croissants (day-old for better texture and absorption)
6 oz sliced ham (deli counter preferred)

Cheese and Dairy

2 cups shredded Gruyere cheese (freshly shredded for better melting)
2.5 cups half and half
6 eggs (room temperature for smoother custard)
4 tbsp unsalted butter (I use Kerrygold)

Vegetables and Herbs

1 yellow onion (thinly sliced into half-moons)
2 tbsp fresh sage (or 1 tsp dried sage)
1 tbsp fresh thyme
Minced chives (optional, adds fresh onion flavor)

Seasonings and Others

1.5 tsp kosher salt
0.5 tsp ground black pepper
1 tbsp whole grain mustard
1 tbsp Dijon mustard
1/8 tsp freshly grated nutmeg (for warm spice notes)
Hollandaise sauce (optional but recommended for richness)

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Instructions

Prepare the Croissants and Ham: Preheat your oven to 350°F (175°C). Slice the day-old croissants into bite-sized pieces and place them evenly into a greased baking dish. Layer the sliced ham over the croissants to ensure every bite has savory flavor.
Cook the Onions and Herbs: In a skillet, melt the unsalted butter over medium heat. Add the thinly sliced yellow onion and cook until caramelized and soft, about 8-10 minutes. Stir in the fresh sage and thyme to release their aromas, then remove from heat.
Combine Custard Mixture: In a large bowl, whisk together the eggs, half and half, Dijon mustard, whole grain mustard, kosher salt, black pepper, and freshly grated nutmeg until fully combined and smooth.
Assemble the Bake: Sprinkle the shredded Gruyere cheese over the ham and croissant layers in the baking dish. Add the caramelized onions and herb mixture evenly on top. Slowly pour the custard mixture over all ingredients, making sure everything is well soaked.
Rest the Mixture: Allow the bake to sit at room temperature for about 10-15 minutes. This helps the croissants absorb the custard and flavors meld beautifully.
Bake the Casserole: Place the baking dish in the preheated oven and bake for about 35-40 minutes, or until the custard is set and the top is golden brown and slightly crisp.
Add Garnishes and Serve: Once baked, optionally top with minced chives and drizzle with warm hollandaise sauce for extra richness and flavor. Serve warm for a comforting, hearty breakfast or brunch.

Notes

Using day-old croissants ensures the dish soaks up the custard without becoming too mushy.
Gruyere cheese melts beautifully and adds a rich, nutty flavor but can be substituted with Swiss if necessary.
The combination of fresh herbs like sage and thyme elevates the savory profile and balances the richness of the dish.
Allowing the dish to rest before baking enhances custard absorption and overall texture.
Hollandaise sauce is optional but highly recommended to add an indulgent finish.
Make sure eggs and half and half are at room temperature to get a smooth, creamy custard.