Preheat the oven to 350 degrees F (180 degrees C) and line two sheet trays with aluminum foil.
Wipe down each White Mushroom (24) with a damp paper towel to clean them off, do not rinse them off because it will make them waterlogged and soggy. Remove the stems to have a nice hollowed out place for the stuffing.
Transfer the prepped mushrooms to the sheet trays. Drizzle each mushroom with Olive Oil (to taste) and sprinkle them with a small pinch of Truffle Sea Salt (to taste) the trays in the oven and roast the mushrooms for 10 minutes to really develop their flavor.
In the meantime, make the filling. In a bowl combine Apple (2), Gruyère Cheese (1 1/2 cup), Seasoned Breadcrumbs (1/2 cup), Apple Sauce (1 tablespoon), Ground Cinnamon (1/2 teaspoon), Truffle Sea Salt (1 pinch), and Butter (2 tablespoon). Stir it together thoroughly to make the filling.
Take the mushrooms out when they are done roasting and stuff each one to the brim with the filling. Put the trays back into the oven to let the mixture meld and get bubbly while the mushrooms get super tender for 15 minutes.
When they're done, take the trays out and let the stuffed mushrooms cool and set for a couple of minutes.