Preheat oven to 325 degrees. Remove stems from mushrooms. Set aside. Finely chop mushroom stems. Place mushroom caps in a shallow bowl and toss with 3 tablespoons of olive oil and Wine or Sherry. Set aside.
Heat remaining 2 tablespoons olive oil in a medium skillet over medium heat. Add fresh chopped veggies. Cook for 2 to 3 minutes, stirring frequently. Add chopped mushroom stems and cook for 2 more minutes. Stir in the scallions and garlic and cook another 2 to 3 minutes, stirring occasionally. Add panko crumbs, stirring to combine evenly with all other ingredients. Finally, swirl in the cream cheese and continue cooking until the cream cheese has melted and made veggie mixture creamy. Turn off heat, stir in Parmesan, parsley, and season with salt and pepper, to taste. Let it cool a bit.
Fill each mushroom generously with veggie mixture. Arrange mushrooms into 1 layer in a large baking dish. Bake until stuffing is browned and crusty (about 40 min). Garnish with squeeze sour cream topping when serving (optional).