Carefully separate the mushroom caps from the stems – just grab each stem with your fingers and twist until it comes off. While you are holding each mushroom, wipe the dirt off the mushroom with a wet paper towel. Put the mushroom caps in one bowl and mushroom stems in another bowl.
Put the mushroom stems in a food processor fitted with a steel blade. Pulse the food processor several times, until the mushroom stems are finely chopped. Move the chopped mushroom stems to a small bowl.
Put the garlic and green onions in a food processor and pulse several times until finely chopped.
Heat the oil in a non-stick frying pan over medium-high heat. Add chopped mushroom stems and cook, stirring occasionally, for 4 minutes. Add chopped green onions and garlic and cook, stirring occasionally, for 2 minutes. Remove the contents of the frying pan to a bowl.
Add cream cheese, Parmesan cheese and pepper to the mushroom stem mixture. Mix until everything is combined. Taste to see if there is enough salt - add salt to taste if necessary.
Line the baking sheet with parchment paper. Put the mushroom caps on the baking sheet. Using a teaspoon, put the filling inside each mushroom. Sprinkle the mushrooms with dried bread crumbs.
Put stuffed mushrooms in the oven and bake for 30 minutes.