breakfast casserole slice on plate

Breakfast casseroles let you fix the morning meal ahead of time — perhaps even the night before — so all you need to do when you wake up is to put the dish in the oven. It’s not exactly breakfast in a hurry, but at least you can have a cup of coffee and relax while you wait, or, should you have invited guests, you can take the extra time to make sure the house (and you!) are company-ready. Recipe developer Jaime Shelbert calls this breakfast casserole recipe "an easy, low stress way to feed a breakfast crowd," so it’s the perfect option for Saturday mornings or family vacations!

"The croissants add decadence and combined with the pancetta and fontina will please any guest," Shelbert describes. Well, maybe not a vegetarian guest, but she does say you can add "veggies such as spinach, tomatoes or broccoli" if you want to omit the meat. Another great thing about this casserole is that it lets you use up any croissants that might be going stale. While the recipe calls for day-old ones, it’s okay if they’re even older! In fact, the drier the croissants, the better, as it facilitates their absorption of the egg mixture. And, if you only have fresh croissants on hand, you can still make the casserole, just allow them to sit uncovered overnight to harden a bit.

Collect the croissant casserole ingredients

ingredients for croissant breakfast casserole

In addition to croissants, you’ll need some cheese for the casserole. Shelbert uses the aforementioned fontina as well as cheddar, but you can use any semi-soft cheeses you wish. She also uses pancetta, but says "you can sub ham or sausage." You’ll also need eggs, milk (Shelbert says to use 2% or whole), olive oil, an onion, some garlic, dried thyme, salt, and Dijon mustard.

Make the egg mixture

egg mixture in white bowl

Start by heating the olive oil in a skillet and cooking the pancetta until it’s just starting to get crisp, something Shelbert says should take about five minutes. Take the pancetta out of the skillet (a spatula or slotted spoon will help), but leave the grease. Use the grease to sauté the onion for about seven minutes, then toss in the garlic and cook for one minute longer until both vegetables are soft and fragrant.

Toss the garlic and onions in with the pancetta, then mix the eggs in a separate bowl with the milk, mustard, and seasonings. Combine the egg mix with the pancetta and onions, then add 1 cup of the shredded cheese.

Assemble the casserole

Torn croissants in pan

Grease up an 11×7-inch baking pan (if you don’t have one, a 9×9-inch dish can be substituted). Tear the croissants into pieces, then scatter them over the bottom of the pan. Pour the cheesy egg mixture over the top, then sprinkle the casserole with the rest of the cheese.

Now comes the important part: let the casserole sit for at least an hour so the egg mixture can soak into the bread. This is where you can just stick the whole thing in the fridge for up to eight hours or overnight, although Shelbert does say, "If [you are] making ahead and refrigerating the casserole, remove [it] from the refrigerator 30 minutes to an hour before baking."

Bake the casserole

baked breakfast casserole in pan

While the casserole is resting, preheat the oven to 350 F. Once you’re ready to bake it, stick it in the oven for 50 to 55 minutes. Check its progress about halfway through. If the casserole is already looking pretty brown, cover it with foil for about the last 20 minutes of baking. Once the casserole is set, which it darn well should be after baking for nearly an hour, take it out of the oven and eat it while it’s still warm.

Shelbert suggests that you serve this dish "with a light fruit salad on the side." If you want something sweet, muffins, donuts, or coffee cake would also be a nice accompaniment, or perhaps some (non-stale) croissants with jam.

  • 2 teaspoons olive oil
  • 8 ounces pancetta, diced small
  • 1 medium sweet onion, diced
  • 2 cloves garlic, minced
  • 6 large eggs
  • 2 cups milk
  • 1 tablespoon Dijon mustard
  • 2 teaspoons dried thyme
  • 1 teaspoon salt
  • 1 ½ cups shredded cheese
  • 4 (12 ounces) day-old croissants
  1. Heat the olive oil in a skillet over medium heat. Cook the pancetta, stirring occasionally, for 5 minutes, until just crisp. Remove pancetta from the skillet but leave the grease.
  2. Sauté the onion in the grease for about 7 minutes. Add the garlic to the sautéed onion and cook for 1 minute more.
  3. Combine the cooked garlic and onions with the pancetta.
  4. Mix the eggs, milk, mustard, thyme, and salt in a separate bowl, then stir the egg mixture into the pancetta.
  5. Stir in 1 cup of cheese.
  6. Lightly grease an 11×7-inch baking dish. Tear the croissants into pieces and arrange the pieces in the bottom of the dish.
  7. Pour the egg mixture over the croissants. Sprinkle the remaining cheese over the casserole.
  8. Let the casserole sit for at least 1 hour before baking.
  9. Preheat the oven to 350 F.
  10. Bake the casserole for 50 to 55 minutes, checking halfway through. If it’s already browning, cover it with foil for the final 20 minutes of baking.
  11. Remove the casserole from the oven when it’s set and serve it warm.