Preheat the oven to 350 F (180 C) and prepare a baking tray by lining it with parchment paper or opt for a glass casserole dish.
Quarter the tomatoes and onion, then arrange them on the baking tray.
Toss the tomatoes and onion in olive oil and roast for 30 minutes.
Combine the cooked tomatoes and onion in a large pot with the cashews, carrot juice, water, bouillon cube, sun-dried tomatoes, garlic, oregano, parsley, basil, and salt.
Let it simmer for 30 minutes over low heat.
Using an immersion blender, blend until smooth.