Easy Make-Ahead Breakfast Casserole

Infinitely adaptable! Use your favorite seasonings, vegetables, meats (or make it vegetarian), cheese, etc.

Easy breakfast casserole you can freeze or make the night before! Use your favorite vegetables, meats, and cheese. Recipe on sallysbakingaddiction.com

I am soooo excited to share today’s recipe with you. It comes from my dear friend Kristen. She made it for us when I visited her in Baltimore last month. As I gobbled it down, I couldn’t stop saying “I have to share this on my blog, I have to share this on my blog, I have share this on my blog.” (Weird blogger life 😐.)

As it turns out, this is something Kristen makes on the regular. And I can see why! Besides taste, this breakfast casserole is pretty impressive in the health category. Full of protein, packed with vegetables. Not only that, it’s so easy to make and adaptable to whatever veggies, cheeses, meats, seasonings you love/have on hand. Confession. I’ve made this 4 times in 3 weeks.

I call it the “CRAZY!! Convenient Casserole.” But easy make-ahead breakfast casserole is a little more descriptive and doesn’t make me sound like a complete lunatic.

Easy breakfast casserole you can freeze or make the night before! Use your favorite vegetables, meats, and cheese. Recipe on sallysbakingaddiction.com

Side note. Did you know that September is national better breakfast month? I believe this means “eat the tastiest breakfasts ever the entire month of September.” (And I have a good idea where you can find some inspiration.)

Wink wink.

Ok but in reality, when Eggland’s Best asked me to share one of my favorite breakfasts to celebrate better breakfast month, this casserole instantly came to mind. Because, as you know, I’ve been obsessing over it nonstop.

I’m Eggland’s Best cheerleader. Love this brand. I prefer EB eggs in this casserole too– because not only is their taste supreme, their calories are lower and vitamins are high. Each EB egg contains 10 times more Vitamin E than ordinary eggs. 💃🏼

Easy breakfast casserole you can freeze or make the night before! Use your favorite vegetables, meats, and cheese. Recipe on sallysbakingaddiction.com

↑ ↑ Soooo much texture and flavor!

This breakfast casserole makes a TON, which I love. I’m talking 12 huge servings, so it’s perfect for dinner or breakfast/lunch the next day. I’ve been eating it on the weekdays instead of my usual cereal/fruit. Feels good to get all those veggies in first thing in the morning and I know Kevin prefers the meat/cheese over granola.

No offense, vanilla almond crunchies.

I took a bunch of step-by-step photos so instead of displaying them all above the recipe, I included them below along with more detailed instructions for you.

I reeeeeeally want you to try this!

Easy Make-Ahead Breakfast Casserole

Makes excellent leftovers for breakfast, lunch, and dinner during the week! Make sure to read the recipe notes and check out all the step-by-step pictures below this recipe before you begin.

Ingredients:

  • 3/4 pound uncooked sausage, casings removed1
  • optional: 1 teaspoon dried rosemary to give the sausage more flavor
  • 2 bell peppers, diced (any color you prefer; about 2 cups)
  • 1 cup sliced mushrooms
  • 1 cup fresh spinach
  • 1/2 medium yellow onion, diced
  • 1 teaspoon minced garlic
  • salt and fresh ground black pepper
  • 4 slices day-old gluten free bread (or whole wheat, white, sourdough, etc)
  • 10 large Eggland's Best eggs
  • 1/2 cup milk (I use almond milk, any milk works)
  • 1/2 cup shredded cheese2

Directions:

  1. Set a large skillet over medium heat and coat it with nonstick spray or a drizzle of olive oil. Place sausage in the skillet and begin to break it up with a spatula or fork. Stir in the rosemary and brown the sausage, about 6-7 minutes.
  2. Meanwhile, set a 2nd skillet over medium heat and coat it with nonstick spray or a drizzle of olive oil. (If you have a skillet large enough to fit both the sausage and veggies, you can just add the veggies to the sausage that is browning in step 1.) Add the peppers, mushrooms, spinach, onion, garlic, and a sprinkle each of salt and pepper. Begin stirring and cooking the veggies down until tender, about 6-8 minutes.
  3. Set sausage and veggies aside.
  4. Generously grease a 9x13 baking pan. Break the bread into pieces and place in the pan in an even layer.
  5. In a large bowl, whisk the eggs, milk, and 1/4 cup shredded cheese together. Pour half of this egg mixture over the bread. Top with the sausage and vegetables, then the remaining egg mixture and remaining 1/4 cup cheese. Add a sprinkle of salt and pepper on top.
  6. Cover casserole with plastic wrap or aluminum foil and refrigerate for 2 hours or overnight-- or up to 1 day. Allow it to come to room temperature before baking.
  7. Preheat the oven to 375°F (191°C). Bake the casserole, uncovered, until the top is golden, edges are crisp, and a toothpick inserted in the center comes out clean-- about 40-45 minutes. I like mine on the super crisp side, so I bake it for around 45-50 minutes. Allow to cool for 10 minutes, then slice and serve. Kevin loves hot sauce on top of his. Try it! Leftovers keep well in the refrigerator for up to 5 days. Reheat in the microwave to your liking.
  8. Make ahead tip/Freezing instructions: Obviously this is a make ahead recipe! However, you can brown the sausage and cook down the veggies up to 2 days in advance-- simply put the two in a tupperware in the refrigerator until ready to use in the recipe. Also, you can freeze this breakfast casserole. Prepare through step 5, then cover the casserole with plastic wrap, then a layer of aluminum foil. Freeze for up to 3 months. Allow to thaw overnight in the refrigerator. Bring to room temperature, then continue with step 7.

Recipe Notes:

The onion, garlic, salt, pepper, and cheese are key to great flavor! Don't leave them out.

  1. Instead of sausage, try browning ground turkey, ground beef, or ground chicken instead. Or use ham. Or cooked shredded chicken. Vegetarians: You can leave out the meat. Just an extra cup (or so) of veggies in its place.
  2. I usually use shredded pepper jack cheese-- other varieties I love for this breakfast casserole are mozzarella, smoked gouda, swiss, and cheddar.

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© Sally’s Baking Addiction. All images & content are copyright protected. Please do not use my images without prior permission. If you want to republish this recipe, please re-write the recipe in your own words, or link back to this post for the recipe.

Alright, here are the step-by-step visuals for you. Plus a few extra tips beyond the written recipe.

First, gather veggies like colorful peppers, mushrooms, and spinach. Like I mention above, you can use your favorite vegetables. I’ve done this with broccoli/peppers, kale/mushrooms, and spinach/zucchini. Try to stick to 3-4 cups veggies total. Cook the veggies down with a little garlic, onion, salt, and pepper. Those last 4 ingredients are where all the flavor comes from, so don’t leave ’em out!

Easy breakfast casserole you can freeze or make the night before! Use your favorite vegetables, meats, and cheese. Recipe on sallysbakingaddiction.com

We like a little meat in the casserole, so I add sausage. Kristen usually uses turkey sausage, so go ahead and use that if you prefer. Instead of sausage, try using ground turkey, ground beef, or ground chicken instead. Or use ham– or cooked shredded chicken. (If you use cooked shredded chicken, you do not have to brown it.)

Vegetarians: You can leave out the meat. Just use some more veggies in its place!

I brown the sausage with some rosemary to give a little flavor. I looooove rosemary with sausage, but you can leave it out if you prefer. Or use another seasoning.

Cook down the veggies and brown the sausage in 1 giant skillet if that’s easier for ya– I don’t have a skillet quite large enough for it all so I did them side by side in separate pans.

Easy breakfast casserole you can freeze or make the night before! Use your favorite vegetables, meats, and cheese. Recipe on sallysbakingaddiction.com

Grab your favorite crusty bread and tear it into little pieces. The bread will be the bottom of the casserole– it soaks up some of the egg and gives the egg casserole texture. Otherwise, you’d just be eating a quiche of sorts.

I’ve been using gluten free bread for my sandwiches lately, so if you don’t eat gluten– you can use your favorite GF variety. Or you can certainly use wheat, sourdough, white, rye, whatever. You’ll need about 4 slices of bread.

Easy breakfast casserole you can freeze or make the night before! Use your favorite vegetables, meats, and cheese. Recipe on sallysbakingaddiction.com

Whisk the Eggland’s Best eggs up with a little milk and cheese. Like the veggies and meat, use whatever cheese you like best. I’ve been using pepper jack cheese for its flavor but I’ve done everything from cheddar to smoked gouda and swiss. So, use your favorite.

Half of the egg mixture goes on top of the bread, then sausage and veggies, then the remaining egg mixture.

Easy breakfast casserole you can freeze or make the night before! Use your favorite vegetables, meats, and cheese. Recipe on sallysbakingaddiction.com

Once the Eggland’s Best eggs are poured on top of it all, you can refrigerate the casserole overnight.

Wake up and all you have to do is throw it in the oven. When we visited Kristen, the morning was totally no-fuss; all she did was brew some coffee and cut up fresh fruit as the casserole cooked.

The crisp edges are my favorite part!

Easy breakfast casserole you can freeze or make the night before! Use your favorite vegetables, meats, and cheese. Recipe on sallysbakingaddiction.com

Have fun, great creative, eat the best breakfast around using Eggland’s Best.  Follow me on Instagram and tag #sallysbakingaddiction so I can see all the SBA recipes you make.

Eggland’s Best provided me with eggs to bring you this recipe. All opinions are my own.

Easy breakfast casserole you can freeze or make the night before! Use your favorite vegetables, meats, and cheese. Recipe on sallysbakingaddiction.com
Easy breakfast casserole you can freeze or make the night before! Use your favorite vegetables, meats, and cheese. Recipe on sallysbakingaddiction.com

122 comments

  1. Hello, thls sounds awesome. This might be a silly question, sorry if it is but I’ve never made a casserole. Does it have to be prepped overnight? What if I just want to make the whole thing in the morning for my family? I’m asking because I don’t know if letting it sit in the fridge over night does something extra for the flavoring. 

    • Step 6 should be helpful– you can cover it and keep it in the fridge for 2 hours – overnight. Letting it sit for sometime, even 2 hours, allows to egg to soak into the bread and the flavors to blend.

  2. Made this a few weeks ago and it was AMAZING!!!

  3. Has anyone made this adding potatoes?

  4. Hi!!
    Can I prepare this ahead Friday to cook Sunday am. And should I leave out the egg mixture until Sunday morning or should I commit all ahead and just warm it up??  

    • Did you get an answer on letting it sit for two days? I prepared mine this morning and want to serve it the day after tomorrow. Do I have to freeze it until tomorrow night or can I let it sit in fridge for two days?

  5. This is a magnificent recipe!!  I subbed bacon (cooked and crumbled into veggies after sautéing) and used 8 oz of shredded pepper jack vs 1/2 c.  My casserole dish was bigger than 13×9, so used 6 slices of gluten-free bread, cubed. Will absolutely make again!!

  6. Looks absolutely fantastic.  Would I  need to double to feed  15 people?

  7. This looks absolutely delicious, Sally! I love that you used so many different veggies. This makes it look so colorful and pretty. 🙂 

    I really want to make this soon! I’m vegan, so I’ll just leave out the sausage and replace the eggs with a mixture of silken tofu, turmeric and kala namak. I did that with a hash brown casserole a couple of weeks ago and it turned out really well (http://veganheaven.org/recipe/vegetarian-breakfast-casserole/). Thanks so much for sharing this!! I seriously can’t wait to give it a try soon. 🙂 

    Sina 

  8. This looks really good. Can I use frozen frozen hashbrowns instead of bread? 

  9. If I replace bread with hash browns, how much would you recommend? Also, do I still need to let it set over night?

  10. Can’t wait to try this out! I was wondering if instead of bread, using small fingerling potatoes? 

  11. I will surely try this, I loved cooking and baking.

    Thank you for sharing. 🙂

  12. Do you have nutritional requirements for this recipe?

  13. I also appreciate the format of your recipes – so much easier to read, and wow! The colors are jumping off the page! Yum!

  14. Love this! Great that you can make ahead! And great that you can freeze! Perfect for making ahead and freezing portions for rushed mornings when you still want something hot! Thanks!

  15. Kind of giggling at myself for making this.  I had some leftover “veggies” and also a renewed determination to feed ’em healthy before sending off to school and work.  So, celery that was starting to go limp, extra green onions from another recipe, cherry tomatoes that were starting to take the term “ripe” to “really gross”, fresh arugula, and sautéed that in extra garlic.   I used the crusts from some sprouted grain bread and leftover chicken maple sausage links. Viola! Everyone loved it – this from 2 kids who think the only acceptable way to eat tomatoes is in ketchup and maybe salsa.  I mean, it looked good, but I thought I’d hear something about at least one of the veggies I put in there.
    I’ve made egg bakes before so why is this one so good?  I don’t think it was the celery 🙂  I’m wondering if it was the bread?  I will remain baffled and will make this very adaptable recipe again.  I really like having another option for my bread crusts.  That bread is so good!

  16. Made this last night and had for dinner tonight. My hubby and I LOVED IT. We both had seconds. Will definitely be making again.

  17. What kind of sausage do you find works best – mild Italian?

    • I’ve made the casserole with several different kinds actually– italian sweet, mild italian, breakfast sausage, smoked sausage– it’s all so good! You can’t go wrong. Just use what you like best.

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