I honestly eyeballed everything, I didn't measure other than sizing up the mushrooms and guessed the measurements. It was also a throw-together using whatever I found in the pantry, refrigerator and freezer.
button mushrooms with stems removed (save them!), seasoned with EVOO and S&P. Saute filling of yellow pepper, mushroom stems, peas & garlic putting them in food processor. Join in bowl with croutons crushed as bread crumbs and Parmesan cheese. Bake in 400° oven for about 20 minutes till golden brown on top.