Before you begin thaw the spinach and squeeze as much liquid as possible. This is crucial, if you do not remove the liquid from the spinach it will result in very soggy mushrooms. I squeeze the spinach dry with my hands, add it to a clean dish towel, and ring as much water as possible. Allow the spinach to sit on the dish towel while you prepare the mushrooms, then ring it out again.

Preheat the oven to 375 degrees F.

Wash the mushrooms and pat dry with a paper towel. Remove the stems. If desired, you can use a metal ½ teaspoon to hollow out the mushrooms. Set the mushrooms aside.

In a mixing bowl, combine the cream cheese, sour cream, green onions, garlic powder, Italian seasoning, mozzarella cheese and chopped spinach.

Stuff the mushrooms with the spinach mixture. Lightly top the mushrooms with the parmesan cheese. Place the mushrooms on a lightly greased baking sheet or casserole dish.

Bake the mushrooms 20-24 minutes or until the tops of the mushrooms are golden brown.