In a dutch oven, heat olive oil over medium heat. Once hot, add onion, celery, carrots, and minced garlic.
Saute until soft, about 8 minutes.
Stir in remaining ingredients.
Raise the temperature to medium-high and heat the mixture to a boil.
Lower the temperature to a simmer and cover. Cook for 35-40 minutes, until the lentils are cooked through.
Use an immersion blender to blend on high about 6-10 pulses. Alternatively, you can remove a few cups of the soup and blend it in a regular blender. If you do this, mix back in. This will thicken the soup and add a richness to it.