Soak cashews in water for 1-4 hours, then rinse and set aside.
Preheat oven to 400° F.
Place the tomatoes (with the cut side facing up), onion, and garlic bulb on a baking sheet. Sprinkle the thyme leaves and salt and pepper over top.
Drizzle with olive oil.
Bake for 30-40 minute or until the edges of the onion, garlic, and tomatoes start to caramelize.
Add roasted tomatoes, onion, desired amount of garlic, and scraped pan drippings to a blender.
Add in the cashew nuts, cayenne pepper, and bouillon. Blend until smooth.
Adjust seasonings to taste and add broth or milk until desired consistency is reached.
Heat, top with fresh or dried parsley, nutritional yeast, or cheese (if desired), and serve.
Notes
Tomatoes: You can use whatever tomatoes you like. The recipe indicates large tomatoes, but you could of course roast Roma tomatoes or Cherry tomatoes and in a pinch you could use jarred tomatoes with or without roasting. The soup's texture will be different but still will be delicious. These fire-roasted tomatoes are a fantastic choice if you go the canned tomato route.
Cashew Alternatives: Hemp seeds or macadamias are a great alternative for the cashews. I haven't tried them yet, but they should work out just fine.