Croissant Breakfast Casserole Recipe

Croissant Breakfast Casserole Recipe: Despite the fact that our Test Kitchen has prepared a large number of breakfast casseroles over the course of its existence, this croissant breakfast casserole continues to be a perennial favorite. This croissant breakfast casserole is a real crowd-pleaser because it is made with mini croissants that have been baked for 12 hours, onions that have been caramelized, and a rich and cheesy egg custard that has a hint of Dijon mustard added to it.

Croissant Breakfast Casserole Recipe

It can also be prepared in advance. Putting together the casserole and putting it in the refrigerator overnight without baking it is possible. The only thing left to do is to place it in the oven when you wake up in the morning. Maintain a close watch on the casserole while it is baking. It is possible for the buttery croissants that are exposed on top to become dark very quickly; therefore, if necessary, tent it with foil while it is still cooking.


  • 2 (5-oz.) country ham steaks, trimmed, bone discarded
  • 2 Tbsp. olive oil, divided
  • 1 1/2 lbs. Vidalia onions or other sweet onions (2 medium onions), chopped (4 cups)
  • 3 oz. baby spinach, roughly chopped (3 cups)
  • 6 large eggs
  • 2 cups whole milk
  • 2 tsp. Dijon mustard
  • 1 tsp. kosher salt
  • 1 tsp. black pepper
  • 6 oz. fontina cheese, shredded (about 1 1⁄2 cups), divided
  • 1 lb. (about 15) day-old mini croissants

Also See:

Crustless Quiche With Spinach And Mushrooms Recipe

How to make it 

  • To chop the ham roughly. (You ought to have one and a half cups.) Within a large skillet, bring one tablespoon of the oil to a temperature of medium. To render the fat, add the ham and continue cooking it for about four minutes while stirring it occasionally.
  • Transfer the ham to a large bowl using a slotted spoon, making sure to save the drippings that are left in the skillet. Fill the skillet with the remaining one tablespoon of oil. Mix in the chopped onions. Cook for approximately thirty minutes, stirring the mixture occasionally, until it has a deep brown color.
  • To wilt the spinach, add it and cook it for one to two minutes while stirring it frequently. Combine the onion mixture with the ham in a bowl, and allow it to cool for ten minutes. In a bowl containing the onion mixture, add the egg mixture and one cup of the cheese, and stir to combine the ingredients.
  • Using a baking dish that is 11 inches by 7 inches and lightly greased, arrange the croissants in two rows, slightly overlapping each other. Put the mixture on top of the croissants. Use the remaining half cup of cheese as a topping.
  • Cover with aluminum foil and place in the refrigerator for eight hours, or even overnight. Bake at 375 degrees Fahrenheit. Remove the lid from the casserole and transfer it to a large baking sheet with a rim.
  • Bake in an oven that has been preheated until the center is set and the top is golden brown, which should take about an hour. To prevent an excessive amount of browning, shield the food with foil after 25 minutes, if necessary.


Q1. What can I add to this casserole in the place of ham steaks?

Instead of ham steaks, you could use cooked sausage or bacon crumbles. You can also leave out the ham completely or use something vegetarian like mushrooms instead.

Q2. Do the croissants for this croissant casserole have to be day-old?

If you want a hearty casserole, croissants that are a day old tend to hold up better than croissants that are fresh. The same thing can be done with fresh croissants that have been lightly toasted in the oven and then let cool before using.

Q3. Why is my breakfast casserole soggy?

If you cover the casserole for some of the baking time, take the lid off for the last few minutes to make the topping crisp and brown. Using croissants that are more than a day old will also help the casserole stay dry.

Q4. How can I tell when my breakfast casserole is done?

When it’s done, the casserole should have a golden brown top and a firm center that you can press.

Leave a Comment