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Cheesy Zucchini Casserole.
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5 from 4 votes

Cheesy Zucchini Casserole

Breakfast casserole packed with mozzarella cheese, fresh zucchini, and a delicious blend of dried herbs. Low-carb, keto-friendly, gluten-free, and vegetarian.
Prep Time20 mins
Cook Time45 mins
Total Time1 hr 5 mins
Course: Breakfast
Cuisine: American
Keyword: eggs, keto, low-carb, vegetarian, zucchini
Servings: 6
Calories: 350kcal
Author: Kelsey Smith


  • 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


  • 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 cheesy zucchini casserole stand for 10 minutes before serving.


  • Nutrition was calculated using MyFitnessPal.
  • For 6 servings: 350 calories, 12g carbs, 21g fat, and 30g protein based on 6 servings.
  • For 8 servings: 262 calories, 9g carbs, 16g fat, and 22g protein.


Calories: 350kcal