Heat some olive oil in a large pot over medium heat. Add the onions, garlic and carrots. Stir it frequently for about 4-5 minutes.
Now add the can of tomatoes (with juices), lentils and vegetable broth. Stir to incorporate everything.
Bring to a boil, then lower heat to a simmer and cook for about 30 minutes, until the lentils are tender and the soup has thickened. For a creamier texture, use an immersion blender to blend a few times in the pot. Alternatively, add 1-2 cups of the soup to a regular blender, blend until smooth and then return to the pot.
