Add your cashews to a container and cover with boiling hot water. Let sit 30-60 minutes to soften.
While the cashews are soaking, chop the broccoli and onion and preheat the oven to 400F.
Add the chopped broccoli and onion to a baking tray. Then, toss with the avocado oil, 2 Tbsp of nutritonal yeast, chili flakes, garlic powder, and salt until evenly coated.
Add the pan of vegetables to the oven and bake for 30 minutes, removing at the 15 minute mark to briefly stir. Then, remove from the oven and let cool.
Once the vegetables are done cooking, strain the cashews and add them to the blender along with the vegetable broth. Turn to the blender to a medium setting and blend for 2-3 minutes until smooth. Next, add in the roasted vegetables, spinach, and an additional 2 Tbsp of nutritional yeast. Blend for another 2 minutes until the soup is super thick and creamy.
Remove the soup from the blender and add it to a pot. Cook over medium heat for 5-10 inutes until the soup is hot. Then, remove from the heat and serve with your choice of toppings. Enjoy!