Addictive Recipes from a Self-Taught Baker

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’m excited to share today’s recipe with you. It comes from my dear friend Kristen, who made it for me when I visited her 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.”

As it turns out, this is something Kristen makes on the regular. And now I understand why. Besides taste, this breakfast casserole is pretty impressive in the health category. Full of protein and packed with your favorite 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. It’s so simple and convenient!

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.)

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 is large. 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.

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

Ingredients:

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

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.
  8. Leftovers keep well in the refrigerator for up to 5 days. Reheat in the microwave to your liking.

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. To do so, 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!

Instead of sausage, try browning ground turkey, ground beef, or ground chicken instead. You can cook bacon and chop it up in this casserole or chop up cooked ham. Vegetarians: You can leave out the meat. Just an extra cup or so of veggies in its place.

I usually use shredded pepper jack cheese. Other varieties I love for this breakfast casserole are mozzarella, smoked gouda, swiss, and cheddar. You can use any cheese you love.

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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. Instead of sausage, try using ground turkey, ground beef, ground chicken, bacon, or ham instead. You can cook the veggies and meat in 1 giant skillet. Vegetarians: You can leave out the meat. Just use some more veggies in its place!

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 eggs 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. Use your fave.

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 eggs are poured on top of it all, you can cover and 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

SHOP THE RECIPE

Here are some items I used to make today’s recipe.

Skillet | Glass Mixing Bowls | Whisk | Wooden Spoon | Glass 9×13 Baking Dish

 

Some of the links above are affiliate links, which pay me a small commission for my referral at no extra cost to you! Thank you for supporting Sally’s Baking Addiction.

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

175 comments

  1. Made this the day before Easter and it was a hit!! I let it cook a little bit longer as I added extra eggs and veggies and sausage, came out perfect. Thanks!

  2. wondering the texture of the bread once it’s baked? I have a weird thing with the texture of soggy bread.

  3. Have you tried baking this and then freezing it in individual serving sizes? It looks AMAZING!

  4. Hello! Can you make this two days ahead?

  5. Do you know about how many calories are per serving? Thanks in advance!

  6. Do you drain the grease after you brown the sausage?? Thanks! 

  7. I need to make it for 60 people.  I’m thinking about  baking it in a large aluminum pan.
    2 Large pans with each pan consisting of 2x your recipe portion.
    I’ll be serving it with a small cuban sandwich with some fruit.
    Do you think it will work baking in the aluminum pan, and do you think 4x will be enough?
    Love you hear your comment!

    Thanks

  8. Can this be frozen?

  9. Could you use diced or grated potatoes instead of bread

  10. Would you suggest ciabatta bread, and any nuts?

  11. Does freezing change the texture of the eggs at all? Or does it taste the same? 

  12. Hi there … a strange question, not about the recipe.

    You show in the pictures above a beautiful fork in a beautiful green color. May I ask where I can get that flatware set?

    I truly appreciate it.

    Thank you!!

  13. Sounds delicious. I am making for a crowd — can you double the recipe and cook in a steam table pan? How many recipes would you need for the large pan? How long would it need to cook? Thanks!!

  14. Have you ever added hash browns to this recipe? How can I incorporate them-my family loves them in egg casseroles.

  15. Can you make this withou the bread?

    • Hi Kim, you can leave the bread out. The texture of the casserole will change– it will just be like baked egg rather than an egg casserole– but it will still have wonderful flavor.

  16. Can you use bacon instead of sausage? Is it best to let the bread get hard, so that when it’s soaking in egg overnight it won’t be soggy?

  17. I would like to make this 2 weeks before Christmas and freeze. Would this be okay being frozen for this long? Also, more importantly, do I have to cook it before freezing? Thank you so much!

  18. I just got finished making my overnight breakfast egg casserole and got a phone call that the breakfast is postponed. Can I freeze it and bake it in a few days .?

  19. This was amazing! I had my girlfriends over for an old school slumber party, so didn’t want to use precious chatting time having to cook brunch the next morning. I cooked the sausage and veg two days before, the day before I whipped up the casserole, and the morning of the brunch, I stuck it in the oven while we went out for a walk in the park. Returned home, voila…magic. I think the quality of the sausage and the farmer’s market veg helped make this stand out even more. Thanks, Sally. You never disappoint.

  20. Hi Sally

    Thanks for this recipe. It was sooo good and I enjoyed the frozen leftovers for a few lunches and dinners. I think I’ll try shredded potatoes or sweet potatoes, like a rosti, instead of bread the next time that I make this.

  21. Thank you for this recipe.  My husband recently went Gluten Free.  I wanted to show him that life hadn’t ended.  He loves this casserole, saying he thought it tasted like pizza!  It freezes well.  

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