Make as many as you want
These are very, very good. When my mother told me this was how Nanny made them, I was sure she was wrong. She wasn't.
I used to use seasoned bread crumbs for this but stopped when I read the list of ingredients on regular brands found in the supermarket. I avoid food with trans fat (hydrogenated oil) and high fructose corn syrup, but if you find a brand of seasoned bread crumbs that you like that doesn’t have junk in it, you can use it here.
Large cultivated mushrooms (just plain old white mushrooms)
Salt and pepper
Pinch of dried oregano (optional - I don't use this, but Nanny and Mom did )
Preheat oven to 350 degrees. Remove stems from mushrooms. Coarsely chop stems and place in a bowl with breadcrumbs (about a quarter of a cup for a large package of mushrooms). Add a small amount of salt and pepper to taste and a little dried oregano if you want to use it.
Do not add any liquid ingredients.
Put mushroom caps open end up in a baking pan. Fill indentations with stuffing mixture, which is totally dry and will fall out a little. Can be prepared in advance to this point.
Drizzle (this means not a lot) with olive oil, and bake for 20 minutes or until sizzling and slightly brown. The cook gets to eat all the little crunchy parts in the bottom of the pan.