Mushroom and Boursin Croissant Breakfast Strata

This year with the boys heading back to school I decided to make a fun breakfast strata for them in hopes of raising everyones spirits as we head back to the books after a nice Christmas break. I was inspired by the many croissant breakfast casseroles I had seen and wanted to try my hand at it as well.
And so, instead of passing up the large box of croissants at Costco this week I told the boys to put them in the cart and away we went. Their spirits were already high and I knew I wouldn’t need all of the croissants for the breakfast casserole so these have turned into really yummy lunches for them as well. A ham and salami sandwich on a croissant was a lunch my son told me, “you can make that for me again on Wednesday.” Got it!
Mushrooms
Next up we purchased some baby bella mushrooms, one of my recent favorite purchases at Costco. You get 1.5 lbs of really big mushrooms which my kids love. If you’re not a Costco shopper cremini mushrooms would work too! I love to get these mushrooms for my slow cooker beef stroganoff recipe, so easy, and my kids love them on a steak as well.
Did you know you never put mushrooms under water to wash them? Simply take a damp towel and them clean off any dirt. I like to pop out the stem as well.
Mushrooms are a food I’d try to get your kid on as early as possible. Many kids may turn their noses up at them, but if they’re seen as a normal part of your diet, I bet they’ll love them. I really wouldn’t sub anything for the mushrooms in this dish. If you wanted to try bell peppers, I suppose you could but you wouldn’t get the deep flavor the mushrooms bring.
I sautéed the mushroom caps in my new favorite large skillet with a little olive oil for about ten minutes on medium-high heat. When it was time to add them to the dish I made sure to not include all the juice that came out of them. I knew they would cook further in the dish and I didn’t want them too cooked down so ten minutes would be my recommended time for you too!

Costco Inspired
This recipe was yet again Costco inspired because I always have their big jar of Italian seasoning on hand. I find it’s a great addition to pasta sauces, chicken dishes, and sausages when I make those.
After the holidays we still had one remaining package of Boursin cheese, known for it’s herb and garlic flavor this was going to be perfect in a breakfast strata. I have used this cheese in pasta recipes as well, but I thought this was a great way to get some more flavor using simple ingredients.
For this strata recipe I also got a large bag of the parmesan blend of cheese. I knew we’d use it with spaghetti nights and it seemed like the perfect cheese to add to this dish. Cheddar cheese would work, but if you’re able to I would get this cheese or a blend of mozzarella and other Italian cheese.
Additions
While I kept the ingredients simple here because I wanted this to come together on a busy morning without too much fuss I didn’t add garlic powder or fresh garlic cloves to the mushrooms while they were sautéing, but you absolutely could. I think this turned out to be such a great looking strata that would be perfect for special occasions. I reminds me a bit of mushroom crepes when it comes to the light bread, cheese filling and loads of mushrooms.
I wouldn’t add much else to this classic recipe in my opinion. It could be served with a side of crispy bacon or sausage and a large mixed green salad for a perfect brunch. If you’re trying to skip all the sweets, especially during breakfast, that we got so used to over the holidays this is a great dish to try.

Boursin and Mushroom Breakfast Strata
Ingredients
- 4 large Croissants from Costco
- 1 TBSP olive or avocado oil
- 1.5 lb baby bella mushrooms, sliced
- 2 tsp Italian seasoning
- 2 tsp kosher salt
- 5 oz package of Boursin cheese garlic and herb flavor
- 2 cups Shredded Italian Cheese such as Parmesan and fontina
- 1 cup heavy cream
- 1 cup whole milk
- 1 ½ TBSP Dijon mustard
- 8 eggs
Instructions
- Spray a 9×13 or similar casserole dish with olive oil.
- Heat oil in a saute pan and start sautéing the mushrooms with 1/2 teaspoon salt and the Italian seasoning. Allow to cook at medium-high for 10 minutes.
- Tear up the croissants and arrange two thirds of them in the prepared dish.
- Tear apart the Boursin and tuck it around the bread and then sprinkle with 1/2 cup of the cheese and 1/2 of the mushroom mixture.
- Add the remaining croissants and top with another 1/2 cup of the cheese and remaining mushrooms, leaving any juice from the mushrooms in the saute pan.
- Whisk together the cream, milk, dijon, remaining salt and eggs. Pour the mixture over the croissants and top with remaining cheese.
- Spray from aluminum foil with oil so it won't stick to the cheese, cover the dish and allow it to sit for 30 minutes before baking.
- While it sits preheat the oven to 350.
- Bake the dish covered for 40 minutes, remove the foil and bake 10-15 minutes longer. Remove from the oven, allow to rest 5-10 minutes and serve right away!
