Clean and dice the zucchini and mushrooms. Then add the vegetables to the broth (by the way, it can be more than 1/4 liter). Bring to the boil briefly (until the stock cubes are completely dissolved), then puree the whole thing with a hand blender, add a dash of Cremefine, done.
Tastes super creamy even though there is no cream in it. Of course, it also works with other vegetables.
Sufficient as a starter for 2 people, eaten alone it is a whole meal that will fill you up.