Baked Egg Casserole ( aka Breakfast Strata) with mushrooms, caramelized onions, goat cheese and thyme, perfect for the holidays. Make it ahead! Video included.
Here’s a little Christmas morning surprise. This Breakfast Strata (aka Egg Casserole) with mushrooms, caramelized onions, goat cheese & thyme is an easy, make-ahead brunch recipe for a lazy relaxing morning. Put this together the night before and refrigerate.
When you wake up Christmas morning, just place it in your oven to bake. When it comes out, it will be puffed and golden and deliciously fragrant. You can also bake this in individual ramekins or mini cast iron skillets for a fun, different presentation. And of course you can make it and bake it the same day too!
Breakfast Strata | 45-second video
We are done catering for the year. I always have to let out a huge sigh of relief after the last catering event of the holiday season because now it’s time to relax. We worked our butts off this year and I’ve been feeling it.
On our first day off, we strapped on our cross-country skis and skied right out the front door. Mother nature was good to us this year and has blanketed our little world with beautiful fluffy white snow. Being outside in the snow actually helps us stave off the winter blues, so we try to get outside often.
On our second day off we went to a movie. It had been so long since I’d been to a movie, I didn’t realize that movie theaters now have commercials before the show, and to my amazement — reclining chairs! What? Where have I been? They were so comfy and cozy, it was impossible not to fall asleep.
The strata starts with eggs and bread. 
Cut a loaf of crusty sourdough or french bread into cubes and toast them in a 400 F oven for 10 minutes.
If adding bacon to the strata, crisp the strips up in the oven at the same time as the bread.
Brian loves his bacon so I added bacon crumbles to his half of the strata. Truthfully, I found myself over on his side of the strata more than I want to admit…the smoky bacon crumbles added a lot of flavor.
Caramelized onions add a lot of flavor too. Thinly slice them and make sure to caramelize them until they are golden brown. 
Saute the mushrooms, season with salt, pepper and fresh thyme. Add the onions to the mix.
Toss the mushroom onion mixture with the toasted bread.
Add the crispy bacon to it if you want. Combine it with the egg mixture, add the goat cheese and place it right in the oven, or refrigerate it until morning.
If refrigerating overnight, make sure to pull the strata out of the fridge and let it come to room temperature first before placing it in the oven, to help ensure even baking.
Bake it covered for the first 35 minutes, then uncovered for last 30 minutes. When it comes out, it will be puffed and golden, crispy on the outside and moist and creamy inside.
Happy Holidays!!
Breakfast Strata with Caramelized Onion, Mushrooms & Thyme
- Prep Time: 20 mins
- Cook Time: 65 mins
- Total Time: 1 hour 25 mins
- Yield: 8 1x
- Category: Breakfast, brunch, eggs
- Method: baked
- Cuisine: northwest
Description
Baked Egg Casserole (called Breakfast Strata) with mushrooms, caramelized onions, goat cheese and thyme, perfect for the holidays. Make it ahead!
Ingredients
- 1 loaf crusty sourdough or french bread, about 8 cups cubed
- 4–5 slices bacon (optional)
- 1 tablespoon oil
- 1 onion – very thinly sliced into rings
- 1–2 Tablespoons butter
- 1 pound of mushrooms sliced
- 3 Tablespoons fresh thyme leaves
- 10 large eggs
- 1 1/2 cups whole milk (or half and half)
- 1 cup sour cream
- 1 teaspoon salt
- 1/2 teaspoon pepper
- 4–6 ounces goat cheese
- thyme sprigs for garnish.
- 1 1/2 cups grated cheese- gruyere, jack, or mozzerella cheese
Instructions
- Preheat oven to 400F
- Cut bread in to ¾ inch cubes and lay on a baking sheet and toast in the oven 10 minutes.
- If adding bacon, spread out on a foil lined baking sheet and bake in the oven 20 minutes or until crisp. (Blot, then cut into small pieces)
- In a large skillet, heat oil over medium high heat. Add thinly sliced onions. Saute, mixing often for 2-3 minutes, then turn heat down to medium low, continuing to cook until golden and tender, about 10 minutes. In another large skillet, heat butter over medium heat. Add sliced mushrooms and cook until tender, about 10 minutes. Add fresh thyme and a generous 3 finger pinch of salt and pepper, and cook off any liquid. Add the caramelized onions to the mushrooms and set aside.
- In a medium bowl, whisk eggs, milk, sour cream, salt and pepper.
- In a large bowl, add the toasted cubed bread. To this add the mushroom-onion-thyme mixture and bacon crumbles if using. Add the grated cheese and ⅔ of the crumbled goat cheese (saving the rest for the top) and gently mix.
- Pour in the eggs and give a gentle stir. Let stand 5 minutes.
- Stir again and pour into a well greased 4 quart baking dish. (At this point you could refrigerate overnight).
- Cover with foil and place the 400 F oven and bake 35 minutes, Uncover, lower heat to 375 F and continue baking 20-30 more minutes until puffed and golden. During the last 10 minutes of baking, scatter the remaining goat cheese over the top and let it melt.
- Garnish with a few thyme sprigs.
Notes
If refrigerating overnight, be sure to remove from fridge 40-60 mins before baking, so it comes to room temperature.
Feel free to add spinach, arugula or other greens to the mushroom mixture for a boost in nutrients.
Nutrition
- Calories: 455
Taste is 5 star – delish
My only complaint is that it took much longer to cook than the recipe stated – closer to an hour and a half.
Maybe my stove temp is off?
Glad you enjoyed this Angela- Did you happen to refrigerate it overnight?
Another fantastic dish! Tried it this morning, wow! Rich, decadent, smoke, salty, savory, creamy, just a delight! Thank you for the inspiration!!!
Glad you enjoyed this!
Great recipe-my only comment is that there is a lot of variation in terms of the size of bread loaves, so it might be helpful to include the number of cups of bread to cubes in the recipe. I bought a sourdough boule for this and it generated WAY too many bread cubes….
Hi Geoff- thanks and updated the recipe to use about 8 cups!
I have made this recipe for over 4 years now. It’s incredible! My absolute favorite breakfast strata. It’s my holiday breakfast/brunch item go to. The flavors are so incredible and this has become a family staple recipe!
Thanks Amber!
do you think I could sub sweet potatoes for the bread in this recipe?
H Hannah! I can’t quite picture it. The bread soaks up the egg batter, so not sure how that would translate here? It might turn out “eggy”.
I loved the strata. Actually I love all things made with eggs that get baked. My hubby doesn’t really love plain mushroom strata. If I add spinach, how much should I add, when to add it and can I use frozen spinach that’s been partially cooked and drained?
Hi Judy- I think adding fresh or frozen spinach would work well here. I think you could toss in the fresh spinach without cooking it. 1-2 cups?
Wondering if possible to substitute gluten-free multigrain bread or bagels for the French bread in this recipe?
It might make it a bit dense, but it would probably work. Just a different texture I’m guessing.
This looks so tasty! Thinking ahead to Christmas, do you think that I could assemble & freeze ahead and then thaw & bake Christmas morning? Thanks!
Hi Leonore, I have not tried freezing this so I don’t know for sure- but I don’t see why this wouldn’t work. 😉
Loved the flavors in this. Took it to a brunch and came home with an empty casserole dish. Success! One question I had when making it, do you use the liquid created when cooking the mushrooms or not?
So the liquid should cook off- I noted the recipe, it wasn’t very clear. Thanks for pointing it out.
5 stars!!
5 stars!! (forgot to rate in my comment just posted)
thanks Pj!
Made this this morning to take as a Christmas offering. So very glad to find this recipe that used goat cheese as my fridge/pantry were pretty bare. Made approx. 1/2 the recipe in a Pyrex glass 2-qt. rectangular dish (12″x7-1/2″). Used a few small crusty breads/rolls from the freezer – approx. 1/2 loaf, warmed and toasted – enough to cover the bottom of the dish). Reconstituted a pkg. of dried shiitake mushrooms (.88 oz pkg made approx. 1-1/2-2 cups reconstituted & chopped). Stir-fried fresh spinach and then celery in oil & garlic (used 2.5 oz, but could have used the full 5 oz pkg since it shrinks down so much). Carmelized a small-med. onion, and added all to the mushrooms. Only had 5 large eggs (just enough, though I would have preferred 6). Only had coconut creamer for the milk. Only had yogurt for the sour cream. Crushed maybe 1/2 tsp dried thyme to mix in. Added 1 Tbl Dijon mustard to increase the flavor, along with salt & pepper. Used all of 4 oz. pkg of goat cheese in bits all across the top and approx. 1/4 c grated Romano (the only 2 cheeses on hand, didn’t want to overpower with the Romano). Cooked in convection countertop oven 400 for 30 min. covered, and then 375 for 18 min. This dish was a minor miracle, given how my first look was thinking I had little I could make. This dish was a big hit, enthusiastically gobbled up with compliments. While I often have made frittatas (easy, quick, can “take” all sort of ingredients), but this is my first strata. Now I know how flexible and forgiving it is, just as frittatas are (though a bit more time-consuming) – and welcome by family and friends who still eat bread & gluten! Thanks for this goat-cheese (a family favorite) version from which I could concoct a success on a day when there was no running to the grocery.
Thanks so much for your detailed notes! Very helpful!
I made this as my vegetarian option for my annual holiday party. It was the favorite for everyone – vegetarians and meat eaters! Thank you for this wonderful recipe; we’ll be making it often!
Im so happy you liked it!
Could you make this without the bread? If so, what modifications would I make?
Hey Mary, I haven’t made this without the bread. My guess is you could make a frittata base, and bake. If you do try it, please leave recipe notes. Thanks!
Hi! This sounds awesome 🙂 Wondering if I could sub Oat or Almond Milk for the Milk & Sour Cream?
Thanks!
I think that would work… or vegan yogurt?
Hi there, I would love to make this and take it to a work function. My travel time is about two hours though. Do you think it would mess it up to reheat it in the microwave once I get there? That would be the only way to heat things at this location. Thank you, Maria
No I think that would be fine!
Brunch guests absolutely loved this! I used croissants because that’s my usual move for anything egg, cheese and mushroom-related. This came together really well- thanks so much for the recipe!
I have made this recipe countless times! It’s always what I make for a big group people and get tons of compliments. The flavors are so complimentary and it is unlike the typical breakfast casserole/strata/bake. Thank you!
So great to hear! Appreciate you letting me know!
I actually made this- Twice in the last week… tastes just as good as it looks and the directions were very simple. Such an elegant dish. Trying to give it “5 Stars” but iPad not cooperating.
Thanks Angie! So glad you like it!!!
I actually made this- Twice in the last week… tastes just as good as it looks and was the directions were very simple. Such an elegant dish.
Thanks Angie! So Glad you enjoyed it!
Hi – if you were to make this in individual ramekins, how many ramekins would you use and how would you adjust the baking time?
Hi Jenn, it depends on the size of the ramekins, but somewhere between 8-12, and yes, I would shorten the cooing time, they will cook faster.
LOVE LOVE LOVE this recipe! Can not wait to try it!
Recipe looks amazing! But those bowls! Where are they from?
Thanks, got them on Easy, shop is closed now though.
I have never heard of strata before, but feel like I need to get to the kitchen straight away to experience it! Overnight dishes are just what you need on Christmas morning, or even anytime when having people round for brunch (who wants to wake up early to prep?!) – and mushrooms, caramelised onion and goats cheese are some of my favourite flavours. Gorgeous photos too! Happy new year, and I hope you had a lovely holiday!
Thank you Claudia …and a Happy New year to you too!!
It looks so delicious, thankyou so much and happy holiday.
This is such a delicious looking breakfast dish. So doable and so SO yummy.
I LOVE your photography and styling as well. Thank you for sharing.
Merry Christmas.
PS: Love those bowls.
Thanks so much…Merry Christmas to you too!!