Wash mushrooms and remove stems. Chop the stems finely.
Heat oven to 350°. Grease a baking dish large enough to hold the mushroom caps in a single layer.
In a skillet over medium heat, melt the butter with olive oil. Add the chopped stems and cook, stirring, for 3 minutes. Add green onions and garlic and continue cooking, stirring, for 2 minutes longer.
Combine the stem mixture with the bread crumbs, cheese, Italian herbs or basil, parsley, salt, and pepper.
Fill the mushroom caps with the stuffing mixture and arrange in the prepared baking dish. Bake for 15 minutes.