Pre-heat the oven to 450°F.
Place a cooling rack over a baking sheet. Thinly slice the eggplant into discs about a quarter-inch thick. Brush the eggplant slices with EVOO on both sides, then season with salt and pepper and roast until browned and tender, 15-18 minutes. Remove and cool, then quarter the discs of roasted eggplant.
Meanwhile, heat about 2 tablespoons EVOO, a couple of turns of the pan, in soup pot over medium-high heat. Add the celery, carrots, onions, bay leaves, pepper, chili pepper, garlic, thyme and oregano and season with salt and pepper; sauté until tender, stirring occasionally, about 10-12 minutes. Add the tomatoes, slicing them up as you drop them into the pot, then add the juice of the tomatoes and stock, plus 1 cup water for thick soup and 2 cups for thinner soup. Simmer the soup at a low boil until the tomatoes break down and the soup develops its flavors, 15-20 minutes. Stir in the roasted eggplant and some torn basil.
Serve in shallow bowls garnished with parsley leaves.