Preheat the oven to 350°F.
Chop the mushrooms and dice the green onion.
In a medium bowl, mix together the cream cheese, sour cream, mayonnaise, and Italian seasoning until smooth.
Stir in the mushrooms and mozzarella cheese until well combined.
Transfer the mixture into a small oven-safe baking dish and spread it out evenly.
Bake for 20 minutes, or until the dip is hot and bubbly.
Top with green onions and serve warm with crackers, bread, or even veggie sticks!