Breakfast casseroles are very popular at our house. This casserole is assembled the night before and refrigerated overnight. Perfect for an easy weekday breakfast or overnight guests. We also love to have this for dinner; you can’t beat breakfast for dinner!!!
Our Test Kitchen has made dozens and dozens of breakfast casseroles over the years, but this one is our latest favorite. Made with day-old mini croissants, caramelized onions, and a rich and cheesy egg custard flavored with a touch of Dijon, this Croissant Breakfast Casserole is a real crowd-pleaser and can be made-ahead. Assemble the casserole and store it, unbaked, in the refrigerator overnight. Then, in the morning, all you have to do is pop it in the oven. Keep an eye on the casserole as it bakes. The buttery croissants exposed on top get dark quickly, so be sure to tent it with foil while it finishes cooking.
This Little Smokie Croissant Breakfast Casserole was a huge hit! How could it not be? Buttery croissants, cheddar cheese, little smokies, eggs and milk. YUM! This recipe calls for a package of mini-croissants. I found the croissants in the bakery section at the grocery store. They came in a 10-oz package.
- 2 tablespoons olive oil
- 1 large yellow onion, sliced thinly
- 2 1/2 cups diced ham (love the Appleton Farms Spiral Sliced Double Glazed Brown Sugar Ham from ALDI)
- 2–3 ounces fresh baby spinach
- 1 cup shredded cheese (obsessed with the Happy Farms Preferred Specialty Shredded Swiss and Gruyere Cheese from ALDI! so genius)
- 12 eggs (love the Simply Nature Organic Cage Free Large Brown Eggs from ALDI)
- 1/2 cup milk
- 1 tablespoon Dijon mustard
- 1 teaspoon salt
- pepper to taste
- 5–6 mini croissants, torn into small pieces (ALDI Village Bakery Mini Croissants – yum)
- Caramelize the Onions: Heat the olive oil over medium-low heat in a large heavy pan. Add the onions and cook, stirring occasionally, for about 30 minutes. End goal: almost-jammy onions that are a reeeally deep, rich, golden brown. (Also, you probably smell like deliciously caramelizey onions now! New signature perfume?)
- Ham and Spinach: Toss the ham in a skillet with a quick drizzle of olive oil. Pan-fry until the edges are kind of browned and some of the fat is rendered. Throw in your spinach. Stir to wilt the spinach. Remove from heat.
- Eggs: Whisk eggs with the milk, dijon, salt, and pepper.
- Layer: Preheat the oven to 350 degrees. Grease a 9×13 baking dish. Layer the ham, spinach, and onions on the bottom. Sprinkle with half of the cheese. Pour eggs over. Arrange croissant pieces on top. Finish with remaining cheese.
- Bake: Cover with foil. Bake for 30 minutes, depending on oven and pan size. Remove foil and bake for another 5-10 minutes. You don’t want to overcook the eggs (gross) but the middle should be almost completely firm when you give the pan a quick jiggle test. You’ll also notice the whole thing will be just starting to puff up a bit. Slice, serve, and brunch forward!