Ratatouille Lentil Soup

Ingredient:

• 5 tablespoons extra-virgin olive oil, divided, plus more as needed and for garnish
• 1 eggplant (unpeeled), cut into 1/2-inch cubes (about 6 cups)
• 2 zucchini, cut into 1/2-inch-thick half-moons (about 3 cups)
• 1 large yellow onion, chopped (about 2 cups)
• 2 tablespoons minced garlic (about 6 garlic cloves)
• 1 teaspoon dried oregano
• 2 tablespoons tomato paste
• 8 cups lower-sodium vegetable broth
• 1 (14.5-ounce) can crushed tomatoes
• 1 cup uncooked French green lentils, rinsed
• 1 (12-ounce) jar roasted red bell peppers, drained and coarsely chopped
• 1 tablespoon kosher salt, plus more to taste
• 1/2 teaspoon black pepper, plus more to taste
• 1/2 cup loosely packed fresh basil leaves, plus more for garnish
• 1 tablespoon balsamic vinegar