Heat 2 tablespoons of olive oil in a large pot over medium heat. Add the onion and carrots and cook for 5 minutes until the onion turns soft.
Stir in the garlic, rosemary, and oregano and cook for 1 minute until the garlic smells fragrant.
Add the lentils, diced tomatoes with their juice, water, salt, and pepper. Bring the mixture to a boil.
Reduce the heat to low, cover the pot, and simmer for 30 minutes until the lentils are tender.
Stir in the remaining 1 tablespoon of olive oil, then taste and adjust salt and pepper if needed.
Ladle the soup into bowls and finish each serving with an extra drizzle of olive oil.