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    Home » Recipes » Vegetarian

    Zucchini Egg Bake

    Published: Jul 11, 2021 · Modified: Sep 26, 2022 by Kelsey Smith

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    This zucchini egg bake is a perfect egg casserole recipe filled with cheese, zucchini sliced, and herbs. This cheesy breakfast casserole is low-carb, keto-friendly, gluten-free, and vegetarian, so it's a recipe that sure to please many diets.

    Zucchini is in season from June through August, and it's one of my favorite summer vegetables. A simple egg casserole is one of my favorite zucchini recipes. Think of this as a crustless quiche.

    My go-to breakfast recipe year-round is pancakes, but this savory summer dish is a seasonal favorite and an easy recipe to use up zucchini from the garden. This works whether you have giant zucchinis or small zucchini.

    This post contains affiliate links. As an Amazon Associate, I earn revenue from qualifying purchases.

    Cheesy Zucchini Casserole.

    Recipe highlights

    • Low carb: This recipe is perfect for a low-carb diet and a keto diet. See the recipe card for total carbohydrates and more nutritional data.
    • Vegetarian: This meatless breakfast casserole is filled with mozzarella cheese, eggs, and zucchini.
    Jump to:
    • Recipe highlights
    • Ingredients
    • Instructions
    • Substitutions and variations
    • Equipment
    • Storage
    • Helpful hints
    • 📖 Recipe
    • Food safety
    • 💬 Comments

    Ingredients

    This recipe calls for a few main ingredients (zucchini, onions, eggs, and cheese) and a beautiful blend of dried herbs.

    Cheesy Zucchini Casserole Ingredients.
    • olive oil
    • fresh zucchini
    • sweet onion
    • large eggs
    • yellow mustard
    • shredded mozzarella
    • dried parsley
    • garlic powder
    • dried basil
    • dried oregano
    • salt
    • black pepper

    See the recipe card for quantities.

    Instructions

    Preheat the oven to 400°F.

    In a large skillet, heat olive oil over medium heat. Cook the onion and zucchini until the zucchini is tender and the onions are translucent. Drain in a colander and allow the veggies to cool for 5–10 minutes.

    Thinly sliced zucchini and onion cooking in a large skillet.

    Tip: To soak up an excess liquid after draining, pat the zucchini dry with paper towels.

    Meanwhile, whisk the eggs, mustard, shredded mozzarella, and seasonings until combined in a large mixing bowl.

    Egg mixture in a mixing bowl.

    When the zucchini has cooled slightly, stir the zucchini/onion mixture into the large bowl.

    Cheesy zucchini casserole filling in a large mixing bowl.

    Grease a 9x13 casserole dish. Pour in zucchini/egg mixture. Smooth over the zucchini mixture so it lays flat. You want flat layers of zucchini.

    Unbaked cheesy zucchini casserole.

    Bake for 35 minutes or until eggs start to brown. Cover with foil and bake for an additional 10 minutes or until a knife is inserted into the center and comes out clean.

    Let the cheesy zucchini breakfast casserole stand for 10 minutes before serving.

    Lightly browned cheesy zucchini casserole

    Substitutions and variations

    Here are a few ideas to remix this recipe to suit your taste (or your fridge contents!).

    • Meat - this recipe would be absolutely delicious with the addition of sausage or bacon. For a casserole of this size, 1lb of breakfast sausage (cooked) or 5–6 slices of bacon (cooked) would be a good add-on.
    • Cheese - I have made this with a blend of mozzarella and cheddar, and it turns out great. A little shredded parmesan cheese would be lovely, too.
    • Mustard - you can absolutely use spicy mustard or brown mustard or whatever kind of mustard you prefer. The mustard adds a little zing to the egg bake.
    • Seasoning - if you don't have basil and oregano, you could substitute these two with 2 teaspoon of Italian seasoning. To add some heat, add a pinch of red pepper flakes.
    • Squash - yellow summer squash can be a good substitution, or it can be used alongside the zucchini slices.
    • Garnish - visually take this dish to the next level with fresh parsley

    If you're on the hunt for a vegan zucchini breakfast egg bake, try Minimalist Baker's Vegan Zucchini Gratin.

    Equipment

    This recipe calls for a 9x13 casserole dish. This is the perfect size baking dish for this recipe.

    If you're in a pinch, I have also made this split across two 9-inch pie plates (same bake time), but it's slightly too much filling, so you would have to leave some out.

    If you make this in a pie plate, I recommend putting the pie plate on top of a baking sheet to avoid a mess from overflowing.

    Storage

    Store cheesy zucchini egg bake covered in the refrigerator (baked) for three to four days or in the freezer (baked) for two to three months.

    Reheat in the microwave in 30-second intervals.

    Slice of Cheesy Zucchini Casserole.

    Helpful hints

    Watch the eggs for browning. At the end of the first 30-minute cook time, keep an eye on the casserole. If they start to brown sooner, go ahead and add that foil over the top to prevent over-browning.

    Lay the zucchini flat. Smooth the zucchini flat into the casserole dish for even baking.

    📖 Recipe

    Cheesy Zucchini Casserole.
    Pin Recipe Save Recipe Saved! Email Print

    Zucchini Egg Bake

    Cheesy zucchini egg bake packed with mozzarella cheese, fresh zucchini, and a delicious blend of dried herbs. Low-carb, keto-friendly, gluten-free, and vegetarian.
    5 from 4 votes
    Recipe by: Kelsey Smith
    Prep time: 20 minutes
    Cook time: 45 minutes
    Total time: 1 hour 5 minutes
    Servings: 6

    Equipment

    • 9x13 baking dish
    • Large frying pan
    • Large mixing bowl
    • Colander

    Ingredients
     
     

    • 1 tablespoon olive oil extra virgin
    • 8 cups thinly sliced zucchini about 6 medium
    • 2 medium sweet onions sliced thinly
    • 6 large eggs room temperature
    • 1 tablespoon yellow mustard
    • 4 cups shredded mozzarella cheese
    • 1 tablespoon dried parsley flakes
    • 1 teaspoon garlic powder
    • 1 teaspoon dried basil leaves
    • 1 teaspoon dried oregano leaves
    • 1 teaspoon salt
    • ½ teaspoon black pepper

    Instructions
     

    • Preheat oven to 400°F.
    • In a large frying pan, heat olive oil over medium heat. Cook the zucchini and onion until the zucchini is tender and the onions are translucent. Drain in a colander and allow veggies to cool for 5–10 minutes.
    • Meanwhile, whisk the eggs, mustard, shredded mozzarella, and seasonings until combined in a large mixing bowl. When the zucchini has cooled slightly, stir in the zucchini/onion mixture.
    • Grease a 9x13 casserole dish. Pour in zucchini/egg mixture. Smooth over the zucchini so it lays flat.
    • Bake for 30–35 minutes or until eggs start to brown. Cover with foil and bake for an additional 10 minutes or until a knife is inserted into the center and comes out clean.
    • Let the casserole stand for 10 minutes before serving.

    Notes

    Storage: Store cheesy zucchini egg bake covered in the refrigerator (baked) for three to four days or in the freezer (baked) for two to three months. Reheat in the microwave in 30-second intervals.

    Nutrition

    Calories: 356kcalCarbohydrates: 12gProtein: 25gFat: 24gSaturated Fat: 12gPolyunsaturated Fat: 2gMonounsaturated Fat: 8gTrans Fat: 0.02gCholesterol: 223mgSodium: 963mgPotassium: 632mgFiber: 3gSugar: 7gVitamin A: 1090IUVitamin C: 33mgCalcium: 452mgIron: 2mg
    Course: Breakfast
    Cuisine: American
    Keyword: eggs, keto, low-carb, vegetarian, zucchini
    Tried this recipe?Rate it to let me know how it was!

    Bookmark this zucchini egg bake recipe, and tell me your favorite ways to use up zucchini.

    Cheesy zucchini casserole square.

    Food safety

    • Cook to a minimum temperature of 160 °F (71.1 °C)
    • Do not use the same utensils on cooked food, that previously touched raw egg
    • Wash hands after touching raw egg or egg shells
    • Do not eat raw eggs
    • Don't leave food sitting out at room temperature for extended periods
    • Don't leave cooking food unattended

    See more guidelines at USDA.gov.

    More Vegetarian

    • Creamy Kale Pasta
    • Biscoff Overnight Oats
    • Chickpea and Spinach Curry
    • Brioche French Toast Casserole

    About Kelsey Smith

    I am a freelance content writer for college-level textbooks by day, mommy by night, and a blogger in between. I live in Knoxville, Tennessee with my husband, Xavier. When I'm not working on college textbooks, you might find me here, sharing recipes, social media tutorials, and more.

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    1. Britny says

      July 30, 2021 at 2:55 pm

      5 stars
      Will definitely be making this a lot!

      Reply
      • Kelsey Smith says

        July 30, 2021 at 4:50 pm

        Hey girl! Love to hear it.

        Reply
    2. Kelsey says

      July 22, 2021 at 11:27 am

      5 stars
      This recipe is also great as a quiche filling. Just pour it into two frozen crusts from the freezer section and bake on a sheet tray for the same amount of time.

      Reply

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    Hi, I'm Kelsey! I am a freelance content writer for college-level textbooks by day, mommy by night, and a blogger in between. I live in Knoxville, Tennessee with my husband, Xavier. When I'm not working, you might find me here, sharing easy comfort food recipes.

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