Wash all the vegetables and chop them into uniform sized cubes. Melt some butter in a frying pan. Add all the vegetables except the potatoes and sauté them over very low heat, so that they do not brown. Add the vegetable broth, salt and pepper.
Boil the potatoes, just until they are somewhat tender but still firm. Add the potatoes to the vegetables. Wash the mushrooms, chop them, and add them to the vegetables. Cook the mixture for 10 minutes. Add salt and pepper to taste, and add the fresh herbs at the end.