Zucchini, Tomato, and Onion Casserole Recipe - Allrecipes.com
Zucchini, Tomato, and Onion Casserole Recipe
  • READY IN 50 mins

Zucchini, Tomato, and Onion Casserole

Recipe by  

"This yummy side dish is a wonderful way to use those homegrown vegetables in the summer. This is great for a cookout served along side grilled steak, chicken, hamburgers, etc.."

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Ingredients Edit and Save

Original recipe makes 8 servings Change Servings
  • PREP

    15 mins
  • COOK

    35 mins

    50 mins


  1. Preheat an oven to 350 degrees F (175 degrees C). Grease a 2-quart baking dish.
  2. Arrange the zucchini slices, tomato slices, and onion slices in alternating layers in the prepared baking dish. Melt the butter in a saucepan over medium-low heat; stir the vinegar, garlic salt, basil, and mustard into the melted butter. Pour the butter mixture over the vegetables; sprinkle the Parmesan cheese over the dish.
  3. Bake in the preheated oven until thoroughly heated, about 30 minutes.
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Reviews More Reviews

Most Helpful Positive Review
Sep 27, 2010

I made this in a skillet, sauteeing all of the veggies and fresh garlic. I did not use the vinegar or mustard. I added the fresh basil at the end and sprinkled the parmesan on top before serving. Let it melt first! My husband came back for seconds!

Most Helpful Critical Review
Jun 01, 2009

The topping was wonderful according to my 6 year old son, he ate most of the topping of the whole thing. However there was too much liquid in it for me. But it wasn't too bad.

Jan 06, 2011

I tried this recipe as written and liked it; however, I have always made it by simply layering the vegetables and adding grated pepper jack cheese just before it is finished baking. Salt & pepper are all that is needed as the tomatoes make enough juice as it cooks. We love it with the pepper jack.

Dec 10, 2009

I double this and put them in layers with alternating thin layers of Mozzarella it held nicely

Sep 09, 2010

I thought this was an excellent combination of flavors, but I did modify it somewhat so that I could prepare it as a skillet veggie side instead of using the oven to bake it. I have created a "custom" recipe for my preparation method...

Aug 17, 2009

I liked this dish but it is a bit on the vinegary side. I might try it out with a very small amount of balsalmic vinegar next time.

Aug 25, 2011

I drizzled veggies with olive oil and layered; made a gluten-free thickened cran-cherry juice sauce from the drippings of six seared chicken breast and baked with pepper jack cheese and garden herbs tucked under the chichen for about 40 minutes. It was delish. Kids loved it and that makes me smile. I did use the produce from my garden. Healthy and Happy. Cheap. Thanks for the recipe!

Oct 18, 2013

Added thinly sliced red skin potatoes, Zucchini, tomatoes, onions omitted vinegar, basil,and mustard, sprinkled with oregano drizzle with olive oil and oregano. Added light layer of shredded Mozzarella then Parmesan. I would rename this to a Gratin -Potato, Zucchini, tomato, and onion. Additional ingredients could include garlic and rosemary.


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  • Calories
  • 205 kcal
  • 10%
  • Carbohydrates
  • 4.5 g
  • 1%
  • Cholesterol
  • 48 mg
  • 16%
  • Fat
  • 17.4 g
  • 27%
  • Fiber
  • 0.8 g
  • 3%
  • Protein
  • 8.6 g
  • 17%
  • Sodium
  • 538 mg
  • 22%

* Percent Daily Values are based on a 2,000 calorie diet.

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