Preheat oven to 350 ℉
Remove the stems from the mushrooms, wash and put aside.
Wash the mushroom caps gently with water, dry with a paper towel, and remove any dirt. Place them in a large bowl with gluten-free Italian vinaigrette. Set aside to marinate.
Chop mushroom stems, scallions, and garlic.
Slip each sausage out of its casing, add a little water to the pan, and follow the instructions for cooking on the package. Crumble up the sausage with a spatula while it sautés. About 15 minutes.
Stir in the chopped mushroom stems and continue to sauté with the sausage, about 3 minutes.
Add the garlic and green onions and continue to sauté for about 3 minutes.
Finally, add the breadcrumbs, and then the bacon.
Add the marscarpone cheese and stir well, continuing to sauté, until creamy and melted into the stuffing.
Remove from heat and allow to cool slightly.
Add parmesan and stir.
Sprinkle with salt and pepper.
Stuff the mushrooms and place them in a baking dish.
Bake for 30 minutes until stuffing is browned.