Clean the mushrooms, cut off the end of the stem and scoop out the inside with a small teaspoon. Peel the remaining vegetables.
Cut the onion into small pieces and fry in a little oil until golden. Finely grate the zucchini and carrots and add to the onions. Let everything stew for 5 - 7 minutes. Add the vegetable stock powder and a little salt and pepper.
Fill the mushrooms with the mixture and don`t skimp on it. Quietly add more so that a hill is formed. Place the mushrooms in a baking dish and sprinkle generously with cheese.
Bake in the preheated oven at 180 ° C top / bottom heat for about 15 minutes until the cheese turns golden.