Pel carrot and cut into small cubes. Rinse and dry bell pepper, remove seeds and ribs, dice finely. Rinse zucchini and cut into cubes.
Heat butter in a saucepan and saute vegetables for a few minutes. Add broth and bring to a boil. Add soy sauce, and season with salt, simmer for 8 minutes on low heat. Season with salt and pepper to taste and add parsley. Pour into bowls and serve.