With soft brush (I use a basting brush) or clean soft cloth, gently wipe any dirt from the mushrooms.
Remove stems and cut a thin slice from top of each mushroom cap so mushrooms are level. Chop stems and thin slices to make 1 cup. Set aside
In saucepan, over medium heat, melt butter. Brush (basting brush) mushroom caps with butter. Place mushroom caps in a shallow baking pan, cavity side up.
Heat olive oil over medium heat (use same saucepan used for butter), add chopped mushroom stems/slices, onion, garlic, and cook until tender. Remove from heat. Add herb stuffing, Neuchatel, bacon bits, parmesan, and parsley. Mix lightly but thoroughly. Spoon about 1 Tablespoon of mixture into each mushroom cap.
Cover with plastic-wrap and refrigerate for 24 hours.