This is the perfect brunch casserole for Mother's Day or Easter with having bonus points for being make-ahead so the morning of you can spend time doing what really matters. This overnight breakfast casserole feels and tastes a little extra special with the use of croissants, leeks and gruyere cheese.

CROISSANT BREAKFAST CASSEROLE 

with ham, leeks and gruyere

 

 

This is THE perfect savory breakfast casserole to add to your Easter or Mother’s Day Brunch. I am telling you it will become a staple year after year. The ingredients make it a little extra special and you make it all the night before!! While it’s sitting in the refrigerator overnight the croissant gets to soak up the custard allowing the flavors meld together.  The presentation is also so beautiful due to the caramelized gruyere cheese on top and the visible layers of the croissant when you cut into it. Those layers of love also serve as pockets to soak up and catch the leeks and ham in the crevices making each bite the perfect bite.

 

This recipe was inspired by a trip I took quite a few years ago to London when my sister and I came across a cute cafe named Gail’s.  It was love at first sight. Gail’s was in a residential area about 20 minutes outside of the city, where we were staying.  We loved this place, or maybe the breakfast sandwich, so much that we ended up stopping there every morning before catching the train. Inside the locals were grabbing a quick breakfast and coffee on their way to work. They had an array of beautifully assorted breakfast options that were adorning the counter so that you can just grab one along with your cappuccino and be on your merry way.  Think light and airy pastries, croissant sandwiches, mini frittatas, everything but the bagel cheese straws & mini bagel loafs stuffed with smoked salmon and avocado. The sight paired with the smell of the espresso filling the air was everything you want in a cafe.  I mean, come on! We all need a Gail’s in our life! 

 

If you haven’t made an overnight casserole before, all you do is follow instructions 1-6 to prepare the casserole the night before. The next morning you’ll casually preheat the oven, pop it out of the fridge, sprinkle it with cheese and just throw it in the oven.  45 minutes later an impressive and delicious breakfast is served without any hassle.

 

As I mentioned the ingredients feel a little extra special with the use of croissants, leeks and gruyere. 

CROISSANTS: Get them from the bakery section of your grocery store, a local bakery or even cafe. If you can’t find croissants you can sub an Italian or other hearty loaf of bread and cut it up into cubes. I’d cover the bottom of the casserole dish with the bread cubes, pour in the custard and then add just enough bread so that the custard is covering all if it.

LEEKS are in the allium family along with onions, scallions and garlic. They have a sweet and mild onion flavor. Be sure to slice them down the middle length wise and either soak and/or rinse them thoroughly in cold water to rid them of sand. They last thing you want in your dish is to have it ruined by sand in it. 

EGGS: Farm fresh are my favorite due to the rich yolks but of course store bought is absolutely fine. 

HALF & HALF is simply just equal parts of heavy cream and milk. So that being said, if you can’t find half and half just substitute 1 1/4 cups of each heavy cream and whole milk. You could also substitute it with light cream which just has a little more milk fat in it.

CREME FRAICHE is thick and creamy with a hint of tanginess, similar to sour cream but thicker and more mild.

PECORINO ROMANO: This is a hard Italian cheese similar to parmsean, which is a great substitute if you have that on hand instead. Pecorino Romano isn’t aged as long as Parmsean therefore it’s not as dry and has more of a saltier umami punch to it.

NUTMEG because you just need that little somethin’ somethin’. 

GRUYERE is a type of Swiss cheese that is a really good  melting cheese. It’s creamy, nutty and slightly salty.

 

This casserole couldn’t be more simple. First, you’re going to slice the croissants in half length wise and line the bottom of the casserole dish with the bottom halves. You may have to cut one in half to fill all gaps. Next, you’re going to sweat the leeks, which just means drawing out the moisture and softening them. This helps to bring out their sweet oniony flavor. To sweat the leeks place a saute pan over medium low heat. Once warmed up, melt a Tbsp of butter and Tbsp of olive oil together. Add in the leeks with a pinch of salt to help draw out the moisture. Occasionally stir for about 5-7 minutes until softened.  While the leeks are sweating, you can work on preparing the custard. In a large bowl combine the eggs, egg yolk, half and half, creme fraiche, pecorino romano and nutmeg. Whisk until thoroughly combined and cohesive. Once the leeks are softened distribute them across the croissant bottoms and then add the ham over the leeks. Now, evenly pour the custard into the casserole dish and arrange the croissant tops, slightly pressing them down into the custard. Cover with plastic wrap and place in the refrigerator for at least 1 hour or preferably overnight. Before baking preheat the oven to 350 and sprinkle gruyere cheese over the top of the casserole.  Bake for about 45 minutes until the center is cooked through. If the top begins to brown too much tent it with tinfoil. 

Ham Leek & Croissant Breakfast Casserole

This is the perfect brunch casserole for Mother's Day or Easter with having bonus points for being make-ahead so the morning of you can spend time doing what really matters. This overnight breakfast casserole feels and tastes a little extra special with the use of croissants, leeks and gruyere cheese.
Prep Time: 8 hours 30 minutes
Cook Time: 45 minutes
Course: Breakfast, brunch
Cuisine: American, French
Keyword: Breakfast, Brunch, Casserole, Croissant, Eggs, make ahead, Overnight
Servings: 8

Equipment

  • 1 9x13 casserole dish

Ingredients

  • 6 Croissants cut in half
  • 1 Leek sliced
  • 5 large Eggs
  • 1 large Egg yolk
  • 2 1/2 cups Half & Half
  • 1/2 cup Creme Fraiche
  • 1/4 cup Pecorino Romano grated
  • 1/4 tsp Nutmeg
  • 1 cup Gruyere Cheese grated

Instructions

  • Slice the croissants in half and place the bottom halves in the casserole dish. Set the top of the croissants to the side.
  • Heat a skillet over medium to medium low heat. Once the pan has heated up melt a tablespoon of butter and add the leeks with a pinch of salt to sweat them. You don't want them to brown, so adjust the heat as needed and occasionally stir for about 5-7 minutes until softened.
  • Fill the croissants: Spoon the leeks over the croissants in the casserole dish distributing evenly. Then arrange the ham on top of the leeks.
  • In a medium bowl thoroughly whisk together the eggs, egg yolk, half & half, creme fraiche, pecorino romano and nutmeg.
  • Pour the custard into the casserole dish and arrange the croissant tops, lightly pressing them down into the custard.
  • Cover with plastic wrap and place in the refrigerator for 1 hour or overnight.
  • Preheat the oven to 350
  • Sprinkle the gruyere cheese all over the top of the casserole and bake uncovered for about 45 min. If it begins to brown too much, tent it with aluminum foil and continue to bake until the center is cooked through.
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