Place the olive oil into a large 6-quart Dutch oven and set over medium heat.
Once hot, add the onion, carrot, celery and salt and sweat until the onions are translucent, approximately 6 to 7 minutes.
Add the lentils, tomatoes, broth, coriander, cumin and grains of paradise and stir to combine. Increase the heat to high and bring just to a boil.
Reduce the heat to low, cover and cook at a low simmer until the lentils are tender, approximately 35 to 40 minutes.
Using a stick blender, puree to your preferred consistency. Serve immediately.
Source: Alton Brown with Food Network