(2) 16 oz. packages whole white mushrooms
3 oz. package cream cheese, softened
1⁄2 cup mayonnaise
1⁄2 cup sour cream
14 oz. can artichoke hearts, drained and chopped
10 oz. package frozen chopped spinach, thawed and squeezed dry
1⁄3 cup shredded mozzarella cheese
3⁄4 tsp. garlic powder
4 Tbsp. shredded Parmesan cheese
2 Tbsp. grated Parmesan cheese
Preheat oven to 400 degrees. Remove stems from mushrooms and discard or save for another use. Clean mushrooms and pat dry with paper towel. Meanwhile, beat cream cheese, mayonnaise, and sour cream in a small bowl. Add artichokes, spinach, mozzarella cheese, garlic powder, and shredded Parmesan cheese.
Fill each mushroom cap with 1 Tbsp. spinach mixture. Place mushrooms on greased baking sheet and sprinkle with grated Parmesan cheese. Bake for 20 minutes or until tender. Transfer to platter and serve warm.