Prepare the Eggplant (Optional): Sprinkle the eggplant with salt and place it in a colander to drain for 20-30 minutes. This helps to remove excess moisture and bitterness. After draining, rinse the eggplant under cold running water, then pat dry with paper towels and set aside.
Sauté the Vegetables: In a large, deep-sided skillet (a nonstick pan is not recommended) with a lid, heat 3 tablespoons of olive oil over medium heat. Add the onions and cook, stirring, until softened, about 3 minutes. Stir in the bell peppers and garlic; cook, stirring often, for 2 to 3 minutes. Add the eggplant and cook, stirring often, for 2 to 3 minutes. Add the zucchini and cook, stirring often, for 3-4 minutes.
Add Tomatoes, Wine, and Seasonings: Stir in the tomatoes and tomato paste, then pour in the wine and simmer for 1 minute. Add the vegetable broth and bring to a simmer over high heat, stirring often. Reduce the heat to medium-high and stir in the thyme, oregano, smoked paprika, and crushed coriander seeds. Season with salt and pepper.
Simmer the Ratatouille: Bring to a brisk simmer. Reduce the heat, cover, and simmer gently for 20 minutes, stirring occasionally.
Add Beans and Cook Further: Add the beans to the skillet, stirring well to combine. Cook, uncovered, until the vegetables are tender yet somewhat firm (or desired consistency) and the liquids have thickened, stirring occasionally, for 10 to 15 minutes.
Finish and Serve: Remove the skillet from the heat and stir in the slivered basil. Serve warm or at room temperature, garnished with basil sprigs if desired.
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