Heat the vegetable oil in a frying pan, fry the legs of the mushrooms until golden brown. Add salt to taste.
Separately fry the onion until golden, add the carrot to it and fry for a couple of minutes. Then add the tomato. As the liquid evaporates, add the sweet pepper. Add salt to taste and fry until the liquid has evaporated and the vegetables are softened.
In a bowl, mix the fried vegetables and the legs of the mushrooms, add the chopped herbs.
Fill the mushroom caps with the resulting mixture and bake them in the oven at 170°C for 25 minutes.