Preheat the oven to 375 degrees F. Line a baking sheet with parchment paper.
Brush the outside of each mushroom with olive oil. Place them top-side down on the prepared baking sheet so that the open side is facing up.
Fill each mushroom with 1 tablespoon of spinach dip. Then top with 1 teaspoon of shredded Parmesan cheese and 1/2 teaspoon of panko.
Bake for 10-12 minutes until the tops are slightly golden brown. Remove from the oven, transfer to a serving platter, and serve warm.
Notes
Nutritional information will vary based on the spinach dip used for the filling. I used my crock pot spinach dip recipe. You can use a premade dip from the store if you don't have leftover dip for the filling.