Preheat oven to 400 degrees Fahrenheit.

In a food processor, pulse bread and garlic until fine crumbs form – set 1/2 cup aside. Add parsley, salt and pepper and pulse until crumbly. Add goat cheese and mix until fully combined.

Remove stems, peels and gills from the mushrooms, and spoon filling into the mushrooms, then place in oiled pan. Put the saved breadcrumbs, along with the walnuts, in the food processor and pulse into fine crumbs. Sprinkle on top of filled mushrooms and bake for 16–18 minutes, or until mushrooms are tender. Serve warm or at room temperature.