Easy Croissant Breakfast Casserole
Buttery, flaky croissants soaked in a rich egg custard and baked until golden and puffed, this Croissant Breakfast Casserole is one of the most elegant brunch dishes you can make with almost zero effort. Loaded with smoky bacon, melted Gruyère cheese, and fresh chives, it comes together in just 15 minutes of prep and delivers impressive, restaurant-quality results every single time.
Equipment
- 9x13-inch baking dish Ceramic or enameled preferred for even heat distribution
- Large mixing bowl For whisking together the egg custard
- Whisk
- Measuring cups and spoons
- Cutting board and knife For chopping chives and dicing bacon
- Aluminum foil For covering the dish during the first phase of baking
- Cooking spray or butter For greasing the baking dish
Ingredients
- 6 large croissants torn into 2-inch pieces; day-old croissants work best
- 8 large eggs
- 2 cups whole milk 480ml
- 1/2 cup heavy cream 120ml; half-and-half can be substituted for a lighter custard
- 2 cups shredded Gruyère cheese about 200g; freshly grated recommended; Swiss or Emmental can be substituted
- 1/2 cup diced cooked bacon about 4-5 strips; cooked and diced; cooked breakfast sausage or diced ham can be substituted
- 2 tbsp fresh chives chopped; green onions can be substituted
- 1/2 tsp garlic powder
- salt to taste
- black pepper to taste; freshly cracked preferred
Instructions
- Preheat your oven to 350°F (175°C). Lightly grease a 9x13-inch baking dish with butter or cooking spray, coating the bottom and sides, then set aside.
- Tear the 6 croissants by hand into roughly 2-inch irregular pieces. Spread the pieces in an even layer across the bottom of the prepared baking dish.
- In a large mixing bowl, whisk together the 8 eggs, 2 cups whole milk, 1/2 cup heavy cream, 1/2 tsp garlic powder, and a generous pinch of salt and black pepper until fully combined and smooth.
- Scatter the diced cooked bacon evenly over the croissant pieces, then sprinkle 1½ cups of the shredded Gruyère on top. Reserve the remaining ½ cup of Gruyère for the topping, then scatter the chopped chives over the cheese layer.
- Slowly pour the egg custard evenly over the entire casserole, then press the croissant pieces down gently with a spatula so they are submerged. For best results, cover and refrigerate for at least 20 minutes or up to overnight.
- Sprinkle the reserved ½ cup of Gruyère evenly over the top of the casserole. Cover the dish loosely with aluminum foil and bake in the preheated 350°F oven for 30 minutes.
- Remove the foil and bake uncovered for an additional 12 to 15 minutes, until the top is deep golden brown, the cheese is bubbly, and a knife inserted in the center comes out clean.
- Remove the casserole from the oven and let it rest for 5 to 10 minutes before slicing and serving. This allows the custard to firm up slightly for cleaner portions.
Notes
- Use day-old croissants: Slightly dry croissants absorb the custard more fully without turning soggy, giving you a creamier, more cohesive texture throughout.
- Do not skip the soaking time: Even 20 minutes of soaking before baking improves the texture significantly. Overnight soaking in the refrigerator gives the best results.
- Grate your own cheese: Pre-shredded cheese contains anti-caking agents that affect how smoothly it melts. Freshly grated Gruyère gives far better flavor and melt.
- Press the croissants down: Before baking, ensure all croissant pieces are submerged or well coated in custard — any dry pieces sticking up will overbrown or burn.
- Cheese substitutions: Swiss, Emmental, Comté, sharp white cheddar, or mozzarella all work well in place of Gruyère.
- Meat variations: Swap bacon for diced cooked ham, crumbled breakfast sausage, or smoked salmon for a different flavor profile.
- Vegetarian option: Omit the bacon and add sautéed mushrooms, roasted red peppers, and baby spinach instead.
- Storage: Cover and refrigerate leftovers for up to 4 days, or freeze (well wrapped) for up to 2 months. Thaw overnight in the refrigerator before reheating.
- Reheating: Reheat covered in a 325°F oven for 15 to 20 minutes for best texture, or microwave individual portions on medium power for 1 to 2 minutes.
- Make-ahead tip: Assemble the unbaked casserole the night before, cover, and refrigerate. Pull it out while the oven preheats in the morning and bake as directed — no extra prep needed.
Nutrition
Serving: 1ServingCalories: 420kcalCarbohydrates: 24gProtein: 22gFat: 27gSaturated Fat: 14gPolyunsaturated Fat: 2gMonounsaturated Fat: 8gCholesterol: 230mgSodium: 580mgPotassium: 210mgFiber: 1gSugar: 5gVitamin A: 18IUVitamin C: 2mgCalcium: 28mgIron: 12mg
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