Oven Roasted Ratatouille

Written by Beth - Budget Bytes

What happens when you take thinly sliced vegetables, layer them in a dish, add a rich red sauce, plenty of herbs, and a cheesy topping? You get this insanely delicious Oven Roasted Ratatouille, aka “the vegetable dish that vegetable haters won’t be able to get enough of.” While this interpretation of ratatouille isn’t exactly traditional, I think you’re going to love it. It kind of reminds me of pizza, but like, made out of really pretty vegetables (and it certainly made my house smell like pizza).

Originally posted 5-19-2014, updated 7-8-2021.

Overhead view of oven roasted ratatouille in the casserole dish with a serving spoon

What is Ratatouille?

Ratatouille is a classic French dish made of stewed vegetables, like tomato, zucchini, eggplant, onion, and bell pepper. It’s rich, comforting, and perfect for sopping up with a piece of crusty artisan bread or ladling over a bowl of polenta. As with most recipes that have been around for generations, there are many interpretations of ratatouille, and I definitely took mine in a different direction.

Rather than stewing the vegetables together in a pot, I chose to make an oven roasted ratatouille, which is a common alternative to the stewed version. Not only is oven roasting the sliced vegetables super pretty, but it’s a little more hands-off than stewing vegetables in a pot, which I appreciate. I also added marinara sauce to the bottom of my casserole dish which ends up mixing with the juices from the vegetables and creating the most delicious sauce (get some bread ready for dipping). Lastly, I topped with cheese, which definitely isn’t the norm for ratatouille, but it sure was delicious! And it really created that pizza-like effect. 

What Size Vegetables to Use

This recipe is extremely flexible. I’ve given some approximate weight values for the vegetables below, but you can really use whatever size you have available and whatever you can squeeze into your baking dish. But a word of advice–once sliced the volume of the vegetables always ends up being more than you estimated, so err on the side of smaller vegetables.

And you don’t have to make the vegetables line up or alternate perfectly in the dish. Just squeeze the slices in there and you’ll be good! I promise it will still taste great even if it doesn’t look perfect. ;) 

What Kind of Baking Dish to Use 

The size of the dish you’ll need will probably vary a bit with the size of your vegetables, but I would suggest using something in the neighborhood of a 9″x11″ rectangular casserole dish, or a 3 quart round dish. You can use a dish made with glass, ceramic, or metal. 

How to Serve Oven Roasted Ratatouille

Oven roasted ratatouille makes a delicious side dish for grilled or roasted meat, like Herb Roasted Pork Tenderloin, Garlic Butter Baked Cod, or Herb Roasted Chicken Breast. You could also serve this as part of a vegetarian meal by pairing it with something like a rich and creamy risotto or serving it on top of a bowl of polenta.

side view of ratatouille in the casserole dish

oven roasted ratatouille with a portion scooped out of the corner
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4.86 from 41 votes

Oven Roasted Ratatouille

Oven roasted ratatouille combines all of summer's delicious vegetables into one rich, flavorful, and beautiful side dish.
Author: Beth - Budget Bytes
Prep Time: 20 mins
Cook Time: 45 mins
Total Time: 1 hr 5 mins
Servings: 8 ¾ cup each


  • 1 cup marinara sauce ($0.50)
  • 1 yellow onion ($0.25)
  • 1 eggplant (about 1 lb.) ($1.49)
  • 1 zucchini (about ½ lb.) ($0.71)
  • 1 yellow squash (about ½ lb.) ($0.55)
  • 3 Roma tomatoes ($0.87)
  • 1 Tbsp olive oil ($0.16)
  • 1/2 tsp dried basil ($0.05)
  • 1/2 tsp dried oregano ($0.05)
  • 1/8 tsp Freshly cracked black pepper ($0.01)
  • 1/8 tsp salt ($0.01)
  • 1 cup shredded mozzarella ($0.94)
  • 1 Tbsp chopped parsley (optional) ($0.09)


  • Preheat the oven to 400ºF. Thinly slice the yellow onion. Slice the eggplant, zucchini, yellow squash, and tomatoes into ⅛-inch thick slices. Cut any pieces with a larger diameter into half-rounds.
  • Pour the marinara in the bottom of a large casserole dish. Sprinkle the sliced onions over top.
  • Begin to line up the sliced eggplant, zucchini, squash, and tomatoes into the dish, standing on their sides, and in an alternating pattern until all of the pieces are used up. Drizzle the olive oil over the vegetables, then sprinkle the basil, oregano, salt, and pepper over top.
  • Transfer the dish to the oven and roast the vegetables for 40 minutes. After 40 minutes, remove the dish from the oven and sprinkle the shredded mozzarella over top. Return the casserole dish to the oven for five minutes, or until the cheese is melted and creamy.
  • After roasting, sprinkle the chopped parsley over top, then serve.


Try to purchase vegetables that are a close size in diameter to make layering easier.
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Serving: 1 ServingCalories: 99 kcalCarbohydrates: 9 gProtein: 5 gFat: 5 gSodium: 291 mgFiber: 3 g
Nutritional values are estimates only. See our full nutrition disclaimer here.

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How to Make Oven Roasted Ratatouille – Step by Step Photos

Eggplant, onion, squash, and tomatoes whole on a cutting board

For this recipe, I used one small eggplant (about 1 lb.), one yellow onion, one yellow squash (1/2 lb.), one zucchini (½ lb.), and three Roma tomatoes. The eggplant, squash, zucchini, and tomatoes are the vegetables that will get layered pretty in the dish, while the onion will be hiding underneath in a base layer.

Sliced eggplant, squash, zucchini, and tomatoes

Preheat the oven to 400ºF. Thinly slice the eggplant, squash, zucchini, and tomatoes. You want everything to be similar in height when placed in the casserole dish, so for pieces with a larger diameter, you’ll want to slice those in half (I did this for the eggplant and larger ends of the squash and zucchini). Aim for ⅛-inch thick slices. 

onion and marinara in the casserole dish

Thinly slice the onion. Spread 1 cup marinara in the bottom of a large casserole dish. Sprinkle the sliced onion over top.

Layered vegetables in the casserole dish

Layer the vegetables in the dish standing up on their sides, like cards in a card catalog (wait, did I just date myself??). They do NOT need to be perfect. Just start squeezing them in as best you can. It’s nice to try to alternate them in a pattern, but once you get toward the end you might have more left of one type of vegetable, so just start popping them in there anywhere they’ll fit. Drizzle 1 Tbsp olive oil over top. Sprinkle ½ tsp dried basil, ½ tsp dried oregano, ⅛ tsp freshly cracked pepper, and ¼ tsp salt on top of the vegetables.

Roasted ratatouille in the casserole dish

Transfer the dish to the preheated 400ºF oven and roast for 40 minutes.

Cheese being sprinkled on top of the ratatouille

After 40 minutes, remove the dish from the oven and sprinkle 1 cup of shredded mozzarella on top. Return the dish to the oven and bake for an additional 5 minutes, or until the cheese is melted and creamy.

Melted cheese on oven roasted ratatouille

Top with a little chopped parsley, then serve!

oven roasted ratatouille with a portion scooped out of the corner

So delicious… and it’s just begging for a beautiful baguette to bathe in it. Mmmmm. You’ve got to spoon some of that sauce from the bottom of the pan onto your plate!

Close up side view of ratatouille in the casserole dish

Closer look? So pretty. I ❤️ vegetables!