Soak the cashew in hot water for 1 hour, drain and rinse.
Into a blender, add soaked cashew and water and blend until creamy. Set aside.
In a large saucepan over a medium heat, warm olive oil. Add onion and cook, stirring occasionally, for about 10 minutes until softened. Add the tomato purée and carrot and cook for 2 minutes. Pour in vegetable stock and simmer for 10 to 15 minutes.
Add the can tomato and cook for another 10 minutes. Into a blender, combine tomato mixture and blend until smooth. Ladle into serving bowls and swirl cashew cream on each.