How many servings does this recipe make?

This recipe makes 4 servings. You can adjust the portion size directly on this page.

What ingredients do I need for Zucchini-Onion Casserole?

You need 10 ingredients. The key ingredients include: 1-1/3 cups sliced zucchini, 3/4 cup water, 1 medium onion, chopped, 1 tablespoon chopped green pepper, and more.

Is Zucchini-Onion Casserole suitable as vegetarian?

Yes, Zucchini-Onion Casserole falls under the Vegetarian category and is a great choice for this type of meal.

How do I store leftover Zucchini-Onion Casserole?

Store leftovers in an airtight container in the refrigerator for up to 3–4 days. Reheat gently before serving.

Zucchini-Onion Casserole Recipe

Name: Zucchini-Onion Casserole
Prep time: 15 min
Cook time: 30 min
Total time: 45 min
Yield: 4 servings
Ingredients: 1-1/3 cups sliced zucchini; 3/4 cup water; 1 medium onion, chopped; 1 tablespoon chopped green pepper; 1 egg; 1/2 cup mayonnaise; 1/3 cup grated Parmesan cheese; 1/4 teaspoon salt; 1/8 teaspoon pepper; 1/3 cup crushed butter-flavored crackers (about 8 crackers)

Try this homemade Zucchini-Onion Casserole recipe the whole family will love. Made with zucchini, water, onion and green pepper. Easy step-by-step instr…

This Zucchini-Onion Casserole relies on simple, everyday ingredients such as sliced zucchini, water, medium onion, chopped and chopped green pepper. It comes together quickly and makes 4 servings, at about 425 kcal each. The step-by-step instructions below are written to be easy to follow, even on a busy day.

It's versatile enough for an easy weeknight dinner yet satisfying enough for guests at the weekend. Serve it with your favorite sides, and keep any leftovers for a quick meal the next day.

Updated Jun 30, 2026

Serves 4 Vegetarian

Tips for the best results

Read through all the steps once before you start and measure out your ingredients first — it makes everything go more smoothly.
Taste as you go and adjust the seasoning before serving.
Avoid overcrowding the pan — cook in batches if needed for the best texture.
Let the dish rest for a few minutes before serving so the flavors settle.
Store leftovers in an airtight container in the fridge and enjoy within a few days.

Variations & substitutions

Use a neutral oil or a plant-based spread in place of butter for a dairy-free version.

No specific allergen information. Please check the ingredient list for possible allergens.

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Zucchini-Onion Casserole

Tips for the best results

Variations & substitutions

My Personal Notes

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