I have heated this soup in the microwave before, but I much prefer making it on the stove top. I don’t like it when the milk particles “separate” and that seems to happen more often with microwave heating.
If you’d like a thicker soup, feel free to substitute diced tomatoes for all or part of the tomato juice. Blend diced tomatoes, juice, and milk with an immersion blender, if needed.
If you need more soup, multiply measurements by number of servings needed.