In a pot over medium heat, add the onion and pepper as well as a tablespoon of water or vegetable broth. Saute until softened, for approximately 3 minutes.
Add the rest of the ingredients to the pot except for the fresh basil. Bring to a boil, then cover and simmer on low heat for 8 to 10 minutes until the lentils have cooked.
Add the fresh basil into the soup. Allow to cool until safe to handle, then using an immersion blender or countertop blender, combine until a smooth soup is formed. Enjoy.