Remove the stems from the mushrooms and place them on a baking sheet with the opening facing up (covered with aluminum foil or baking paper, it will produce a lot of juice). Cut the stalks into small pieces and sauté in the butter with the chopped onion and the grated apple.
Season with salt, pepper and rosemary, then glaze with honey. Pour the mixture into mushrooms and sprinkle the cheese on top. Bake in the oven for about 15 minutes at 180 ° C, alternatively you can of course wrap the filled mushrooms in aluminum foil and grill them.
The combination of apple and mushroom is unusual, but also unusually tasty. If necessary, you can just fill the mushroom caps with the finely chopped raw stems, as well as apples and onions, without searing them.