Ingredients:
- 6 Large Croissants (day-old preferred)
- 1 Tbsp Unsalted Butter, for greasing
- 1 1/2 cups Diced Cooked Ham (cubed)
- 1 1/2 cups Gruyère Cheese, grated
- 2 Tbsp Fresh Chives, minced
- 6 Large Eggs
- 1 cup Whole Milk
- 1/2 cup Heavy Cream
- 1 tsp Granulated Sugar
- 1 tsp Dijon Mustard
- 1/2 tsp Fine Sea Salt
- 1/4 tsp Freshly Ground Black Pepper
- Pinch freshly grated Nutmeg
Instructions:
- Prep the Dish and Croissants: Generously grease a 9x13 inch baking dish with the butter. Slice the day-old croissants into large, 1-inch cubes.
- Layer the Solids: Arrange half of the croissant cubes snugly in the prepared baking dish. Scatter half of the diced ham and half of the grated Gruyère cheese over this layer. Repeat the layering process with the remaining croissants, ham, and cheese, pressing down gently.
- Make the Custard: In a large mixing bowl, whisk together the eggs, whole milk, heavy cream, sugar, Dijon mustard, salt, pepper, and nutmeg until completely smooth. Avoid over-whisking.
- Soak and Chill: Slowly pour the prepared custard evenly over the croissants, ensuring every piece of pastry is moistened. Cover the dish tightly with plastic wrap and refrigerate for a minimum of 4 hours, or preferably overnight (up to 24 hours). This rest is crucial for texture.
- Temper and Preheat: About 30 minutes before baking, remove the casserole dish from the fridge. Preheat the oven to 375°F (190°C).
- Bake (Covered): Place the dish into the preheated oven. Bake for 25 minutes, covering the dish loosely with foil to prevent the croissant tops from browning too quickly.
- Finish Bake (Uncovered): Remove the foil and continue baking for another 20–25 minutes, or until the top is golden brown and the custard is fully set. A knife inserted into the center should come out mostly clean.
- Rest and Serve: Remove from the oven and let the casserole rest for 10 minutes before serving. This allows the internal structure to firm up. Sprinkle the minced chives over the top before cutting and serving.