Sauté the Vegetables: Heat 2 tablespoons extra virgin olive oil in a large pot over medium heat. Add 1 onion, 2 carrots, 1 leek, and a pinch of salt. Cook for about 5 minutes, stirring often, until soft and fragrant.
Add Flavor: Stir in 3 cloves garlic, ¼ teaspoon red pepper flakes, 3 tablespoons tomato paste, and 2 bay leaves. Cook for 1 minute, stirring, until the tomato paste darkens slightly.
Simmer the Soup: Add 3 cans lentils, 1 can crushed tomatoes, 1 teaspoon dried oregano, 4 cups vegetable broth, ½ teaspoon salt, and pepper. Stir well, then simmer gently for 15 minutes, or until the soup thickens and flavors come together.
Finish and Serve: Stir in 2 tablespoons red wine vinegar, then taste and adjust seasoning. For a creamier texture, blend a cup of soup and mix it back in. Serve warm with olive oil, feta, and crusty bread.
