Roasted Ratatouille with Pan-fried Onions

Fragrant layers of bright zucchini, tender Japanese eggplant, and juicy romas - all roasted to perfection in a nest of herby, garlicky tomatoes and pan-fried onions. 

Jump to:

• What's the Story Behind this Recipe?
• Why this Recipe Works
• What Goes into Ratatouille
• How to Make this Recipe
• FAQs & Expert Tips
• More Fresh Vegetarian Recipes
• Ratatouille with Pan-Fried Onions

What's the Story Behind this Recipe?

Originally from the South of France, ratatouille is an amazingly versatile dish, both for the cook and as a meal. Traditionally made with a base of tomatoes, zucchini, onions, eggplant, garlic, and herbs, home chefs around the world add everything from potatoes to porcinis to the mix.

No one makes ratatouille like we do. In fact, it seems like E-V-E-R-Y-O-N-E puts their own flare on this simple summer vegetable medley. We make ours on a bed of pan-fried onions for extra sweetness and depth of flavor. Oh, my Gosh! You will not believe how much rich umami flavor those onions add!

Why this Recipe Works

Some cooks make ratatouille entirely in a pot on the stove, others roast it in the oven. You can even make it in a slow cooker or an Instant Pot! The whole idea is, once you have the basic ratatouille recipe down, feel free to make it your own.

And here's a little secret... (shhhhh....)

When it comes to making ratatouille, it really doesn't matter how you put it together. 

It's true! Whether you choose to "fussy up" and camera-ready your ratatouille, or just throw everything in the dish and let the chips fall where they may, the fragrant flavors of all those fresh summer veggies and herbs will magically combine to create something your tastebuds will love.

What Goes into Ratatouille

Ratatouille is best when made with the freshest veggies possible.

Ingredient Notes & Substitutions

★ Japanese Eggplant is more tender than Italian eggplant (aubergines), and works better for this dish. However, if you cannot find Japanese eggplant, you can definitely use small Italian eggplants as a substitute. The important thing is to cut it in approximately the same size as the other veggies you will be using so everything cooks evenly.

★ Tomatoes: Use meaty sauce tomatoes, like romas. It is best to use whole slices of tomato.

★ Zucchini: (i.e., courgette) Use young, tender medium-sized zucchinis. (Avoid those garden monsters you forgot to pick yesterday!)

★ Onions: Use red or yellow onions. Avoid using sweet onions for this recipe.

Yellow and red onions have more of those pungent lachymators (i.e., stuff that makes you cry) than do sweet onions (e.g., WallaWallas, Vidalias, etc.), giving the impression that they are significantly less sweet.

The truth is that yellow and red onions actually have a far more complex flavor profile, and yield richer, more flavorful pan-fried onions.

How to Make this Recipe

Uniform Slices: Be sure to slice your vegetables uniformly to all be approximately the same size and thickness so that everything cooks evenly.

Preheat oven to 350°F | 180°C. Spray a deep-dish pie plate with cooking spray and set aside.

Heat a cast iron or heavy skillet over medium-high heat. When a water droplet sizzles on the surface, add 2 teaspoons of olive oil and swirl to coat skillet.

Carefully place whole onion slices on the skillet. Allow the onion slices to brown and crisp on one side for a few minutes, and then carefully turn them over using a spatula and brown the other side.

Allow onion slices to cool, and then separate onion rings from one another and set aside.

Make an herb mixture by combining the dried oregano, thyme, rosemary, salt, pepper, and chili powder in a small bowl. Set aside.

In a medium bowl, combine crushed or diced tomatoes, remaining 2 teaspoons of olive oil, vinegar, garlic, fresh basil, and all but 1 teaspoon of the herb mixture.

Pour the tomato mixture evenly into the bottom of a deep dish pie plate. (I use my cast iron pie dish.)

Fussy Prep

Arrange sliced veggies around the edge of the plate in a pattern that makes you happy. (I did tomato-zucchini-eggplant-zucchini-eggplant-repeat.)

Put the pan-fried onion mixture in the middle of the veggie-ring. Arrange more veggies in the middle, until you are either out of veggies or space, whichever comes first.

OPTIONAL: At this point, you can spray the whole thing with a little cooking spray or brush it with just a bit of olive oil to encourage browning if you would like. Doing so also seems to make the whole thing look better after it is done roasting.

Sprinkle remaining dried herb mixture over the top of the prepared ratatouille.

Bake in preheated oven for an hour, or until the sauce is bubbly and the veggies are tender (but not mushy!!)

Garnish with fresh basil and freshly grated Parmesan or Romano.

Fast & Easy Prep

If you don't care if your ratatouille is picture perfect, just pour the crushed tomato mixture into a baking dish and top with pan-fried onions. Arrange the veggies evenly across the top, and bake as directed.

FAQs & Expert Tips

Marry the Flavors

Ratatouille and similar foods (i.e., spaghetti sauce, lasagna, and eggplant parm) almost always taste better "the next day," after flavors have had a chance to marry and mellow.

I'm sure that there is a scientific explanation for this phenomena, but whatever the reason, keep this in mind if you plan to serve this dish to company. We often make meals like this a day ahead of time, refrigerate overnight and reheat to serve.

More Fresh Vegetarian Recipes

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