Roughly chop up cauliflower and onion. Place in a Crockpot along with cashews and broth. Submerge the cauliflower and cashews under the broth as much as possible, then cover and cook until cauliflower is tender (high for 3 to 4 hours, low for 6 to 8).
When cauliflower is tender, blend the mixture until smooth using either a handheld immersion blender or by carefully transferring to a countertop blender.
Stir in 1 to 2 cups of water, until you reach a thick, soupy consistency (it will differ depending on the size of your cauliflower. Season with salt and serve.
Preheat oven to 400 degrees F. Toss chickpeas with oil, spices, and salt. Spread onto a parchment-lined baking sheet and bake for 20 to 25 minutes, or until crispy. Serve warm over soup.