Quick Recipe Version (TL;DR)
Quick Ingredients
- 2 tbsp + 2 tbsp olive oil (divided), plus more as needed
- 1 medium yellow onion, diced
- 4 garlic cloves, minced
- 1 medium eggplant (about 12 oz / 340 g), 3/4-inch dice
- 2 medium zucchini (about 14 oz / 400 g total), 3/4-inch dice
- 2 bell peppers (any color), 3/4-inch dice
- 1 (28 oz / 794 g) can whole peeled tomatoes, crushed by hand
- 2 tbsp tomato paste
- 1 tsp kosher salt + more to taste; 1/2 tsp black pepper
- 1 tsp fresh thyme leaves (or 1/2 tsp dried); 1 bay leaf
- 1 tbsp balsamic vinegar
- Polenta: 1 cup (170 g) polenta, 3 cups (720 ml) water, 1 cup (240 ml) whole milk, 1 tsp kosher salt, 2 tbsp unsalted butter, 1/2 cup (50 g) grated Parmesan
- Basil oil: 1 packed cup (30 g) basil leaves, 1/2 cup (120 ml) extra-virgin olive oil, 1/8 tsp kosher salt, 1 tsp lemon juice
Do This
- 1. Heat oven to 325°F (163°C). Start ratatouille base on the stove (onion, garlic, tomato paste), then add veg + tomatoes.
- 2. Slow-roast ratatouille uncovered for 75 minutes, stirring once halfway.
- 3. Cook polenta (25 minutes), stir in butter and Parmesan; spread into an 8×8-inch pan and chill 60 minutes.
- 4. Make basil oil: blanch basil 10 seconds, blend with olive oil, salt, and lemon.
- 5. Cut chilled polenta into 12 squares; pan-sear in olive oil 3–4 minutes per side.
- 6. Spoon ratatouille over polenta squares and drizzle with basil oil.
Why You’ll Love This Recipe
- Big flavor, low fuss: the oven does most of the work while the vegetables turn silky and sweet.
- Great texture contrast: jammy ratatouille over crisp-edged, creamy polenta squares.
- Make-ahead friendly: polenta and ratatouille both reheat beautifully.
- Fresh finish: vibrant basil oil makes the whole dish taste bright and restaurant-worthy.
Grocery List
- Produce: 1 yellow onion, 4 garlic cloves, 1 medium eggplant, 2 medium zucchini, 2 bell peppers, 1 packed cup fresh basil, 1 lemon (for juice, optional but recommended)
- Dairy: whole milk, unsalted butter, Parmesan cheese
- Pantry: polenta, canned whole peeled tomatoes (28 oz / 794 g), tomato paste, olive oil, balsamic vinegar, kosher salt, black pepper, thyme (fresh or dried), bay leaf
Full Ingredients
Slow-Roasted Ratatouille
- 2 tbsp olive oil
- 1 medium yellow onion, diced (about 1 1/2 cups)
- 4 garlic cloves, minced
- 2 tbsp tomato paste
- 1 medium eggplant (about 12 oz / 340 g), cut into 3/4-inch cubes
- 2 medium zucchini (about 14 oz / 400 g total), cut into 3/4-inch cubes
- 2 bell peppers (about 12 oz / 340 g total), cut into 3/4-inch pieces
- 1 (28 oz / 794 g) can whole peeled tomatoes, crushed by hand (include juices)
- 1 tsp kosher salt, plus more to taste
- 1/2 tsp freshly ground black pepper
- 1 tsp fresh thyme leaves (or 1/2 tsp dried thyme)
- 1 bay leaf
- 1 tbsp balsamic vinegar
Creamy Polenta (for Cutting into Squares)
- Nonstick spray or 1 tsp olive oil (for the pan)
- 1 cup (170 g) medium-grind polenta
- 3 cups (720 ml) water
- 1 cup (240 ml) whole milk
- 1 tsp kosher salt
- 2 tbsp unsalted butter
- 1/2 cup (50 g) finely grated Parmesan cheese
Bright Basil Oil
- 1 packed cup (30 g) fresh basil leaves
- 1/2 cup (120 ml) extra-virgin olive oil
- 1/8 tsp kosher salt
- 1 tsp fresh lemon juice
For Searing and Serving
- 2 tbsp olive oil (for pan-searing the polenta), plus more as needed
- Small basil leaves (optional, for garnish)
- Extra Parmesan (optional, for serving)
Step-by-Step Instructions
Step 1: Prep the pan and preheat the oven
Set a rack in the middle of the oven and preheat to 325°F (163°C). This lower temperature helps the vegetables soften slowly and concentrate in flavor without scorching.
Choose a wide, heavy oven-safe pot or Dutch oven (about 5 to 6 quarts) so the vegetables roast rather than steam.
Step 2: Build a flavorful tomato-onion base
Place the Dutch oven over medium heat and add 2 tbsp olive oil. Add the diced onion and cook for 6 minutes, stirring occasionally, until softened and lightly translucent (no need to brown deeply).
Add the minced garlic and cook for 30 seconds until fragrant. Stir in the tomato paste and cook for 1 minute to caramelize it slightly; this deepens the final flavor.
Step 3: Add vegetables and slow-roast until silky
Add the eggplant, zucchini, and bell peppers to the pot. Pour in the crushed tomatoes with their juices. Season with 1 tsp kosher salt, 1/2 tsp black pepper, thyme, and the bay leaf.
Stir well, then transfer the uncovered pot to the oven. Roast for 75 minutes, stirring once at the 40-minute mark, until the vegetables are tender, the sauce is thick and glossy, and the top has a little concentrated, roasted look around the edges.
Carefully remove the pot from the oven. Stir in 1 tbsp balsamic vinegar. Taste and add more salt if needed. Remove and discard the bay leaf.
Step 4: Cook the polenta until creamy
While the ratatouille roasts, cook the polenta. In a medium saucepan, bring 3 cups (720 ml) water, 1 cup (240 ml) whole milk, and 1 tsp kosher salt to a gentle boil over medium-high heat.
Reduce heat to medium-low. Slowly whisk in the 1 cup (170 g) polenta in a steady stream to prevent lumps. Cook for 25 minutes, stirring frequently (every 1 to 2 minutes), until thick, creamy, and the grains are tender.
Turn off the heat. Stir in 2 tbsp butter and 1/2 cup (50 g) Parmesan until melted and smooth.
Step 5: Set the polenta for neat squares
Lightly grease an 8×8-inch pan with nonstick spray or 1 tsp olive oil. Pour the hot polenta into the pan and smooth the top with a spatula into an even layer.
Cool on the counter for 15 minutes, then cover and refrigerate until firm, 60 minutes. (It should feel set and slice cleanly.)
Step 6: Make the basil oil (bright green and fragrant)
Bring a small saucepan of water to a boil. Prepare a bowl of ice water nearby.
Add the basil leaves to the boiling water for exactly 10 seconds, then immediately transfer to the ice water for 30 seconds. Drain and squeeze the basil very dry (this helps the oil stay vividly green and not watery).
Blend the blanched basil with 1/2 cup (120 ml) extra-virgin olive oil, 1/8 tsp kosher salt, and 1 tsp lemon juice for 45 to 60 seconds, until smooth. For an extra-refined look, strain through a fine-mesh sieve; for a more rustic finish, keep it as-is.
Step 7: Cut and pan-sear the polenta squares
Run a thin knife around the edges of the chilled polenta and turn it out onto a cutting board. Cut into 12 squares (a 3×4 grid).
Heat 2 tbsp olive oil in a large nonstick or well-seasoned cast-iron skillet over medium heat. Add the polenta squares in a single layer (work in batches if needed). Sear for 3 to 4 minutes per side, until golden and crisp on the outside.
Transfer to a plate and lightly season with a pinch of salt if desired.
Step 8: Plate and finish with basil oil
Place 3 polenta squares on each plate. Spoon a generous amount of the slow-roasted ratatouille over the top, letting the sauce pool around the edges.
Drizzle with 1 to 2 teaspoons basil oil per serving. Garnish with a few small basil leaves and a little extra Parmesan if you like. Serve warm.
Pro Tips
- Cut vegetables evenly: aiming for 3/4-inch pieces helps everything finish at the same time and keeps the texture pleasantly chunky.
- Roast uncovered: this is key for concentration; the sauce thickens and the vegetables taste sweeter and deeper.
- Stir once, not constantly: minimal stirring encourages light caramelization on the top and edges.
- For ultra-crisp polenta: after cutting, pat the squares dry with a paper towel before searing.
- Keep basil oil bright: blanching and drying the basil thoroughly prevents dull color and bitterness.
Variations
- Make it spicy: add 1/4 tsp red pepper flakes to the onion-garlic base, or finish with a few drops of chili oil alongside the basil oil.
- Add protein: top each plate with a poached egg or serve with seared chicken thighs or white beans stirred into the ratatouille (1 1/2 cups cooked beans).
- Herb twist: swap half the basil with flat-leaf parsley for a greener, slightly peppery oil.
Storage & Make-Ahead
Ratatouille: Cool and refrigerate in an airtight container for up to 5 days. Reheat gently on the stovetop over medium-low heat for 8 to 10 minutes, adding 1 to 2 tbsp water if it has thickened too much. It also freezes well for up to 3 months.
Polenta squares: Keep cooked, chilled polenta (uncut or cut) covered in the refrigerator up to 3 days. Sear just before serving for the best crust. You can also sear ahead and rewarm on a sheet pan at 350°F (177°C) for 10 minutes.
Basil oil: Store in a small jar in the refrigerator for up to 3 days. Bring to room temperature for 15 minutes and stir before drizzling.
Nutrition (per serving)
Approximate, based on 4 servings: 520 calories, 26 g fat, 60 g carbohydrates, 14 g protein, 10 g fiber, 760 mg sodium.
