Preheat the oven to 400F and line a baking sheet with parchment.
Slice the tops off the garlic bulbs, so the cloves are showing. Drizzle the tops with a bit of olive oil. Wrap in foil, and roast for 40 minutes, until the cloves have softened.
In a pot over medium heat, add the chopped yellow onion, potatoes and carrots. Saute until fragrant, approximately 5 minutes. Add the thyme and rosemary and toss until the vegetables are covered in the spices.
Add the vegetable stock, cashews and sunflower seeds. Bring to a boil, then simmer, covered for 35 minutes, until the potatoes are cooked and can be pierced with a fork.
Remove the garlic from the oven, and when safe to handle, squeeze into the pot of soup.
Now, in batches, you can either transfer this to a blender, or use an immersion blender to combine until a smooth soup is formed. Enjoy with chives, salt and black pepper, croutons and vegan parmesan as desired.