Prepare the vegetables: Wash and trim the ends off the eggplant and zucchini. Cut them into uniform 2.5cm (1 inch) cubes. Place the eggplant cubes in a colander, sprinkle with 1 tsp (approx. 6g) of salt, and let sit for 30 minutes to draw out excess moisture and bitterness. Rinse the eggplant cubes thoroughly and pat them completely dry with paper towels. This step is crucial to prevent a watery ratatouille.

Prepare the bell peppers: Wash and core the bell peppers, removing the seeds and membranes. Cut them into 2.5cm (1 inch) pieces, similar in size to the eggplant and zucchini.

Prepare the onion and garlic: Peel and finely dice the yellow onion. Peel and mince the garlic cloves.

Sauté the aromatics: Heat 3 tbsp (45ml) of olive oil in a large, heavy-bottomed pot or Dutch oven over medium heat. Add the diced onion and cook, stirring occasionally, until softened and translucent, about 5-7 minutes. Add the minced garlic and cook for another minute until fragrant, being careful not to burn it.

Cook the vegetables in batches: Add the prepared eggplant cubes to the pot. Cook, stirring occasionally, until lightly browned and tender, about 6-8 minutes. You may need to add a little more olive oil (1 tbsp / 15ml at a time) if the pot becomes too dry. Remove the eggplant from the pot and set aside. Repeat this process with the zucchini cubes, cooking until lightly browned, about 5-7 minutes. Remove and set aside with the eggplant. Finally, add the bell pepper pieces to the pot and cook until slightly softened, about 5 minutes. Remove and set aside.

Build the tomato base: Add the remaining 3 tbsp (45ml) of olive oil to the same pot over medium heat. Stir in the tomato paste and cook for 1 minute, stirring constantly, until it darkens slightly. Pour in the crushed tomatoes, add the Herbes de Provence, salt (remaining 0.5 tsp / 3g), and black pepper. Stir well to combine. Bring the mixture to a simmer.

Combine and simmer: Return the sautéed eggplant, zucchini, and bell peppers to the pot with the tomato sauce. Add the fresh thyme sprigs. Stir gently to coat all the vegetables evenly. Reduce the heat to low, cover the pot, and let the ratatouille simmer gently for at least 30-45 minutes, or until all the vegetables are very tender and the flavors have melded beautifully. Stir occasionally to prevent sticking.

Adjust seasoning and finish: Remove the thyme sprigs. Taste the ratatouille and adjust seasoning with additional salt and pepper if needed. The vegetables should be very tender but still hold their shape. If the ratatouille seems too liquidy, you can simmer it uncovered for the last 10-15 minutes to allow some of the excess liquid to evaporate.

Serve: Ladle the warm ratatouille into bowls. Garnish generously with fresh chopped basil leaves. Ratatouille can be served hot, warm, or even at room temperature.