Step 1

In a Dutch oven or large pot, heat 2 tablespoons of the olive oil over medium heat. Add the eggplant, season generously with salt and pepper, and cook, stirring occasionally, until browned in spots, about 2 minutes. Transfer to a large bowl.

Step 2

In the same pot, heat 2 more tablespoons of the olive oil over medium heat. Add the zucchini and yellow squash, season generously with salt and pepper, and cook, stirring occasionally, until browned in spots, about 2 minutes. Transfer to the bowl with the eggplant.

Step 3

Return the pot to medium heat and add the remaining 2 tablespoons of olive oil. Add the onion and red bell pepper, season with salt and pepper, and cook, stirring occasionally, until softened and just beginning to brown, 6 to 8 minutes.

Step 4

Stir the garlic, thyme, bay leaf and tomatoes into the pot then stir in the reserved vegetables. Bring to a simmer, then continue to simmer for 1 hour or until everything has melded together.

Step 5

Fish out the bay leaf and thyme sprigs and discard. Taste the ratatouille and season with salt and pepper to taste. Finish with Parmesan cheese and stir in the basil. Serve with a nice drizzle of olive oil.