Place the onion, carrot, celery and broccoli in a large pot. Add 6 cups water, basil and salt to the pot and stir. Bring to a boil over high heat then cover and reduce heat to a low simmer.
Let simmer for 15 to 20 minutes or until broccoli is tender.
Meanwhile, in a blender, create your cashew cream. Blend together the cashews and remaining 1 cup water. (If you adjust the serving size, just keep the cashew to water ratio 1:1.)
Pour the cashew cream into the pot with the veggies and stir.
Add the green lentils and stir again.
Add the spinach to the blender, and carefully (let the pot of veggies cool a bit first!) blend the soup in batches until smooth.
Ladle into bowls, drizzle lightly with olive oil and top with freshly ground pepper, if desired. Enjoy!
Notes
To store: Refrigerate in an airtight container for up to four days.