Preheat the oven to 375 degrees F. Line 2 sheet pans with parchment paper.
Toss the sweet potatoes, onion and cauliflower with 1 tablespoon avocado oil and cumin. Spread into a single layer on the prepared sheet pans. Roast until the vegetables start to brown at the edges and the sweet potatoes are tender, about 30 minutes. Toss halfway.
Add the cooked sweet potatoes, cauliflower, onion and white beans in a blender or food processor. Add the veggie stock and blend. Top with leftover veggies.