Preheat oven to 400 degrees F.
Grease a baking sheet with cooking spray. Set aside.
Carefully, rinse the dirt off of the mushrooms. Do not soak mushrooms in water. Instead, wipe off the dirt with a damp paper towel or lightly rinse under cool water and dry them with a towel carefully.
Remove, but do not discard, them stems. Set aside. Place the mushroom caps on the baking sheet.
Finely chop the mushroom stems, onions and garlic.
In a medium skillet, melt butter and add chopped mushroom stems. Cook for about 5 minutes, until most of the moisture has been removed.
Add in the onions and garlic. Cook for 3 minutes, until the onions have softened.
Add in the red wine vinegar and stir together.
Add panko breadcrumbs and spices and stir together. Let the breadcrumbs toast in the mixture, for about 3 minutes, stirring occasionally to ensure it doesn't burn.
Remove from heat. Let cool for 5 minutes.
Add mushroom mixture to a bowl, along with the vegan parmesan, vegan cream cheese, fresh thyme and parsley. Stir together well.
Fill the mushrooms caps with the filling, but do not overfill. They will puff up a bit while cooking.
Bake until the tops are golden brown, 20-25 minutes.