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Slow Roasted Ratatouille

This slow roasted ratatouille is summertime in a pan! A velvety puree of onions, celery, carrots, and peppers lays the foundation for a beautiful topping of thinly sliced zucchini, eggplant, tomatoes, and yellow squash, crowned with a touch of thyme, garlic, and olive oil. This impressive dish captures the essence of summer in every delectable bite.

top view of cooked ratatouille on wooden background

This was outstanding! Curiously enough though, it was even better on day two. And so, what I suggest is to put it together over the weekend and then reheat for dinner during the week. Why the weekend you ask? Well, this recipe calls for baking on low (280 degrees) for 3 hours – but don’t worry, since it’s mostly hands off time and is well worth it because you will want to eat lots of these veggies.

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Why You Should Make This!

Bursting with Fresh Summer Flavors: This recipe takes advantage of abundant fresh summer produce, including zucchini, eggplant, tomatoes, and yellow squash. By using these vibrant ingredients at the peak of their flavor, you’ll create a dish that truly celebrates the essence of summer.

Healthy and Nutritious: Ratatouille is a wholesome and nutritious dish. It’s packed with vitamins, minerals, and antioxidants from the variety of vegetables used in the recipe. The combination of flavors and textures makes it a satisfying and guilt-free option for a nourishing meal.

Versatile and Adaptable: Ratatouille is a versatile dish that can be enjoyed in various ways. It can be served as a side dish, a main course, or a topping for pasta or crusty bread. Its versatility allows you to get creative and tailor it to your preferences.

Simple yet Impressive: Despite its impressive presentation and complex flavors, Ratatouille is surprisingly simple to make. With a few basic ingredients and straightforward techniques, you can whip up a visually stunning dish to impress your family and friends.

Vegetarian and Vegan-Friendly: This Ratatouille recipe is perfect for vegetarians and vegans, as it is entirely plant-based. It provides a satisfying and flavorful option for those following a meat-free lifestyle or looking to incorporate more vegetables into their diet.

Ingredients Needed to Make

For the puree:

Onion: Adds savory flavor and acts as a base for the puree.

Carrots: Provides natural sweetness and adds depth to the puree.

Celery stalks: Contributes a refreshing and slightly herbal note to the puree.

Garlic: Infuses the puree with a robust and savory taste.

Red bell pepper: Adds a tangy and slightly sweet flavor to the puree.

Poblano pepper or chili peppers: Provide heat and depth of flavor to the puree.

Crushed tomatoes: Creates a rich tomato base and adds texture to the puree.

Basil leaves: Infuses the puree with a fresh and aromatic herbal flavor.

Salt: Enhances the overall taste and brings out the flavors of the ingredients.

Pepper: Adds a subtle touch of spiciness and balances the flavors.

Herb de Provence: A blend of dried herbs, typically including thyme, rosemary, marjoram, and other aromatic herbs, that adds a distinctive Provençal flavor to the puree.

For the sliced vegetables:

Japanese eggplants: Provide a creamy texture and subtle flavor to the Ratatouille.

Roma tomatoes: Offer a rich and juicy taste to the dish.

Yellow squash: Adds a bright and slightly sweet flavor to the Ratatouille.

Green zucchini: Brings a mild and crisp taste to the dish.

For the topping:

Olive oil: Used for drizzling over the sliced vegetables, adds richness to the dish.

Garlic: Infuses the topping with a bold and savory taste.

Thyme leaves: Provide an aromatic and earthy flavor to the topping.th

Salt: Enhances the overall seasoning and balance of flavors.

Pepper: Adds a hint of spiciness and complements the other flavors.

vegetables sliced and chopped for ratatouille on wooden board
Top: sliced vegetables (yellow squash, green squash, tomatoes, eggplant), diced cucumber; Center: peppers, crushed tomatoes, bell pepper; Bottom: diced onion, herbs de Provence; salt; thyme, olive oil, fresh herbs (thyme, basil), garlic, diced carrots.

How to Make

For the puree:

In a large sauté pan, heat oil over medium heat. Add the onion, celery, carrots, and garlic. Sauté until the vegetables are softened and a fork can easily be inserted into the carrots.

chopped vegetables in cast iron pan

While the vegetables cook, char the peppers under the broiler or on an outdoor grill until all sides are blackened. Rotate them to ensure even charring. Once charred, transfer the peppers to a bowl and tightly cover with plastic wrap or place them in a ziplock bag to cool. Once cooled, peel off the skins.

peppers on pan ready to roast
peppers on sheet pan after roasting
covering peppers with plastic wrap in glass bowl

In a blender, combine the softened vegetables (carrot, celery, onion, garlic), canned tomatoes, charred peppers, basil, herbs, salt, and pepper. Puree the mixture until smooth.

vegetable cooked and roasted and ready to puree
puree in glass cup on wooden board

To prepare the dish for baking:

Preheat the oven to 280°F (140°C).

Spread the puree evenly on the bottom of an oven-safe skillet or tart pan (12 inches to 16 inches in size). Arrange the sliced eggplant, tomatoes, and zucchini on top in a swirl pattern.

arranging slices of vegetables over puree in pan

Sprinkle the vegetables with salt and pepper.

In a small bowl, combine the olive oil, garlic, and thyme. Drizzle this mixture over the vegetables.

sprinkling seasoning over vegetable slices after arranging in pan

Cover the skillet or tart pan with aluminum foil and bake for 3 hours.

Once baked, it is recommended to refrigerate the dish overnight to allow the flavors to marry and mingle.

To serve:

Preheat the oven to 350°F (175°C).
If the ratatouille is cold from refrigeration, bake uncovered for 45 minutes. If the dish is warm or hot, cook uncovered for 20 minutes.

Once baked, the Ratatouille is ready to be enjoyed. The extended cooking time and refrigeration overnight enhance the flavors, making each bite even more delicious.

plateful of ratatouille with gold fork

Storage and Make Ahead

Storage: Ratatouille can be stored in an airtight container in the refrigerator for up to 4-5 days. This allows you to enjoy the flavors over multiple meals or as leftovers. When reheating, gently warm it on the stovetop over low heat.

Make Ahead: Ratatouille can be prepared in advance, making it a convenient option for meal planning or entertaining. After assembling the dish, refrigerate it for up to 24 hours before baking. This allows the flavors to meld together even more. When ready to serve, simply bake it at 350 F uncovered for 45 minutes (if cold) or 20 minutes if warm/hot.

📖 Recipe

top view of cooked ratatouille on wooden background

Slow Roasted Ratatouille

An amazingly delicious recipe for ratatouille that is slow-roasted – a perfect way to pack plenty of vegetables onto your dinner plate! You will LOVE this!
5 from 5 votes
Author: Marie
Prep Time 45 minutes
Cook Time 4 hours
Total Time 4 hours 45 minutes
Course beverage
Cuisine American
Servings 8
Calories 92 kcal


  • oven safe skillet or tart pan 12 to 18 inches in diameter (size will vary depending on thickness of vegetable slice and size of vegetables)


For the puree

  • 1 onion , chopped
  • 2 carrots , chopped
  • 2 celery stalks , chopped
  • 1 tablespoon garlic , minced
  • 1 red bell pepper
  • 1 poblano pepper and 2 chili peppers
  • 28 oz crushed tomatoes
  • basil leaves handful
  • 1 teaspoon salt
  • 1/2 teaspoon pepper
  • 1 teaspoon herb de Provance

For the sliced vegetables

  • 2 Japanese eggplants sliced thinly
  • 6 Roma tomatoes sliced thinly
  • 2 yellow squash sliced thinly
  • 2 green zucchini sliced thinly

For the topping

  • 2 tablespoons olive oil
  • 1 or 2 cloves garlic minced
  • 1 teaspoon thyme leaves chopped (I used dried but fresh would be better)
  • salt and pepper to taste


For the puree

  • Add oil to a large saute pan and then add and cook the onion, celery, carrots and garlic over medium heat until softened (until a fork can be easily inserted into the carrots)
  • In the meantime, char the peppers under the broiler or on an outdoor grill until charred on all sides (rotate to blacken all sides) (see this post)
  • Place the charred peppers in a bowl covered tightly with plastic wrap or in a ziploc bag until cooled, then peel off skins
  • Add softened vegetables (carrot, celery, onion, garlic), canned tomatoes, peppers, basil, herbs and salt/pepper to blender and puree the mixture

To prepare the dish for baking

  • Preheat oven to 280 F (140 C)
  • Spread the puree on the bottom of an oven safe skillet or tart pan and then arrange the sliced eggplant, tomatoes and zucchini in a swirl fashion on top
  • Sprinkle with salt and pepper
  • Combine the olive oil, garlic and thyme and then drizzle on top of vegetables
  • Cover with aluminum foil and bake for 3 hours
  • At this point, it is recommended to refrigerate overnight to allow flavors to marry and mingle
  • To serve, heat oven to 350 F (175 C) and bake uncovered for 45 minutes (if cold) or 20 minutes or warm/hot


Calories: 92kcalCarbohydrates: 13gProtein: 3gFat: 4gSaturated Fat: 1gPolyunsaturated Fat: 1gMonounsaturated Fat: 3gSodium: 313mgPotassium: 634mgFiber: 5gSugar: 8gVitamin A: 3682IUVitamin C: 58mgCalcium: 40mgIron: 1mg
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Adapted from Bruno’s Kitchen


  1. 5 stars
    I have made this recipe three or four times and it is amazing EVERY time. It’s so delicious and hearty and the leftovers are alway wonderful. Thanks for this great dish!

  2. 5 stars
    Delicious. Made this recipe for a party. Everyone raved and asked for the recipe. It is a bit time consuming to make, but not difficult. I will definitely make again.

  3. Made this for a dinner party was a huge success use the leftovers over spaghetti noodles delicious and healthy

  4. I made this last weekend and left it for a day to marinate (as suggested)…it was phenomenal. Slow roasting is definitely the way to go. We ate more the next day and it tasted EVEN better than the day before. Wonderful recipe with perfectly detailed directions and lovely photos. Thank you so much!

    1. Hi Kelly – hard to say because it will vary depending on size of your vegetables. You can probably just layer it looser to get less in or tighter to fit more and if you have too much left over, maybe use it in a quiche or frittata? I love eggplant as a pizza topping and squash in minestrone soup!

      1. 5 stars
        This was fantastic!!!! I have tried a ratatouille before and signed the dish off as a mediocre side dish only. I am so glad I found your site and this recipe. It’s so light yet surprisingly hearty– main delicious dish all the way. Thank you so much! Definitely adding to the recipe book! Yay!!

  5. 5 stars
    I made this Sunday afternoon. So easy to put together, and great to sit and read while the scent of my tasty roasted dinner wafted by! Though I took it out too early, I scooped a little extra out before returning the dish to the oven! It is so delicious, I ate myself sick.

    I was bummed when I got home from the store to see I’d forgotten a red pepper. If it tasted this good without the pepper, I can’t wait to try it with it. Last night (and tonight) I served it with naan dipped in a spicy oil. Delicious. Future plans include: white bean, quinoa, brown rice. Delicious! Thank you!

  6. 5 stars
    What size pan does this recipe need?

    I made this in December and it was so good That I’m making it for a dinner party and wanted leftovers so I quintupled the recipe. … Not sure I have a large enough pan to do it in one batch.

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