Ham and Cheese Croissant Breakfast Casserole

Ham and Cheese Croissant Breakfast Casserole

Generous pieces of croissant bake with folded ham and Swiss cheese in a tender, set egg custard. The uneven top turns golden while the interior stays soft enough to scoop from the dish.

A short soak helps the croissants absorb the custard; there is no need to refrigerate the casserole overnight. Because the exposed tops can brown before the middle finishes cooking, use the set center—not the color or the clock alone—to judge when it is done.

Ingredients for Ham and Cheese Croissant Breakfast Casserole

• 1 tablespoon unsalted butter, for the dish
• 8 large croissants, about 1 pound (450g), preferably day-old
• 8 ounces cooked ham (225g), thinly sliced or chopped
• 2 cups shredded Swiss cheese (200g), divided
• 8 large eggs
• 1 1/2 cups whole milk
• 1/2 cup heavy cream
• 1 tablespoon Dijon mustard
• 1/2 teaspoon kosher salt, or less to taste
• 1/4 teaspoon black pepper

Day-old croissants hold up well during the soak, but fresh ones work too. Season the custard lightly because the ham and Swiss already contain salt.

How to Make Ham and Cheese Croissant Breakfast Casserole

1. Prepare the dish: Preheat the oven to 350°F (175°C). Butter a 9-by-13-inch baking dish. Tear the croissants into generous, irregular pieces and arrange them loosely in the dish, leaving some flaky tops exposed.
2. Add the ham and cheese: Tuck most of the ham and about half the Swiss between the croissant pieces. Leave a few folded pieces of ham visible near the top, and reserve the remaining cheese.
3. Add the custard: Whisk the eggs, milk, cream, Dijon, salt, and pepper until combined. Pour evenly over the croissants. Gently press down pieces that sit above the liquid, checking the edges for dry spots.
4. Soak: Let the casserole stand for 20 to 30 minutes. The croissants should look moistened, not completely submerged.
5. Bake covered: Sprinkle the reserved Swiss over the top. Cover loosely with foil, keeping it off the croissants, and bake for 20 to 25 minutes.
6. Uncover and finish: Remove the foil and bake for about 20 to 30 minutes more, until the tops are golden and the center is set. Start checking around 40 minutes total; expect about 45 to 55 minutes for the bake, though a chilled casserole may take longer. If the top darkens before the center sets, loosely replace the foil and continue baking.
7. Rest and serve: Let the casserole rest for 10 minutes so the custard settles and portions hold together more easily. Serve warm from the baking dish.

How to Tell When the Center Is Done

Gently move the dish: a slight jiggle in the very middle is fine, but the custard should not slosh. A knife inserted near the center should not show loose liquid egg. If the top is browned but the middle is still fluid, cover loosely with foil and keep baking in short increments.

If using an instant-read thermometer, 160°F (70°C) at the center is a general food-safety reference for egg dishes.

Make-Ahead Instructions

For the make-ahead option, cover the casserole after adding the custard and refrigerate it for up to about 8 hours. Add the reserved cheese just before baking. Bake directly from chilled, allowing extra time as needed for the center to set.

How to Store and Reheat Leftovers

Cool leftovers, then refrigerate them in a covered container for up to 3 days. Reheat individual portions in a 300°F (150°C) oven until warmed through. A microwave is quicker but may soften the croissants.

Freezing is also an option, though the guidance is limited. Cool the casserole completely, wrap it tightly, and freeze for up to 2 months. Thaw overnight in the refrigerator, then reheat at 350°F until heated through.

Nutrition

Approximate nutrition per serving, based on 8 servings: 535 calories, 25g protein, 34g fat, and 30g carbohydrates. Per 100g: 250 calories, 12g protein, 16g fat, and 14g carbohydrates. Values will vary with the croissants, ham, and cheese used.