Heat the olive oil in a large pot or Dutch oven over medium heat.

Add the diced onion, carrots, and celery. Sauté for 5 to 7 minutes until the vegetables soften and the onions become translucent.

Stir in the minced garlic and cook for 1 additional minute until fragrant.

Add the rinsed lentils, diced tomatoes with their juices, and vegetable broth to the pot. Stir well to combine.

Bring the soup to a boil, then reduce the heat to low. Cover and simmer for 30 to 35 minutes, or until the lentils are completely tender.

For a creamier texture, use an immersion blender to partially blend about 2 cups of the soup.

Ladle the warm soup into bowls, garnish with freshly chopped cilantro, and serve immediately with slices of crusty bread.