Remove the stems from the mushrooms and chop them finely. Set aside.Using a spoon, remove the gills (the black part) from the mushrooms and discard them. Set aside.Marinade:In a large bowl, combine all the ingredients.Add the whole mushrooms and coat them well.Let marinate for 1 hour.Preheat the oven to 400 F (200 C).Line a baking sheet with a silicone mat.Filling:In a pan, cook the bacon until golden brown.Add the chopped mushroom stems, asparagus, bell pepper, and onion.Season with salt and pepper.Continue cooking for about 2 minutes.Add the broth and bring to a boil. Reduce until almost dry.Add the bread cubes and mix well. Set aside.Remove the mushrooms from the marinade and place them on the baking sheet.Season with salt and pepper.Divide the filling among the mushrooms and sprinkle with cheese.Bake in the oven for 20 minutes or until the cheese is lightly browned.