This recipe uses much more maneagable portions of ingredients - and should be much easier to cook.
2 Lbs mushrooms, properly chosen and cleaned - 40 or 50
8 oz bread, crumbed
1/2 C finely chopped onion
1/2 C finely chopped celery
1/2 t green spices - marjoram, oregano, tarragon, thyme
2 cloves garlic
1/2 C powdered cheese - Parmesan or Romano
1 T olive oil
Buy a 16 oz loaf of bread - I used sourdough (Northern Californian specialty) several days ahead of time, cut the loaf in half, and preserve one half for normal eating. Take the other half, cut or break into slices or chunks, and let it dry out, in an oven if necessary. Turn them into crumbs, in a food processor. Dry crumbs are best - they get moistened later.
Remove the stem from each mushroom. This is where large, slightly stale mushrooms are best. Set the caps and stems aside.
Peel and finely chop the garlic - in a food processor. Remove the garlic from the food processor, and set aside.
Chop the mushroom stems in the food processor, into crumbs, next.
Chop the bread into crumbs, as finely as possible, in the food processor, last. The hard bread crumbs help scrub the mushroom and garlic off the food processor container. Mix the cheese into the crumbs while processing. Combine the bread crumbs and cheese thoroughly, and set aside.
Heat up a Dutch Oven until water droplets sizzle when dropped in. Add Olive Oil. Add garlic, saute very briefly. Crumble the spices (crush them with your fingers) into the garlic, add onions and celery, mix well and saute until onions are transparent and slightly soft. Add chopped mushrooms, mix well and saute until they start to give off water. Turn off the heat, and let the veggies cool a bit.
Add the cooked veggies to the bread crumb and cheese, mix well. The bread / veggies will turn into a thick ghooey paste - which is good. You want a pasty mixture so it will stick inside the mushroom caps.
Preheat the oven to 400F. Start stuffing the mushroom caps. I found it works best to just scoop up a teaspoon or so of stuffing, turn the spoon over and gently pack the stuffing into the cap. Scrape the spoon in both directions for an attractive, mounded effect. Just pack the stuffing in slightly, and put on a baking sheet. Mushrooms are not like cookies - you do not have to leave expansion room - they will shrink as they cook.
Fill up one baking sheet, stick it in the (by now) heated oven. Let it cook 15 - 30 minutes, until the stuffing is brown on the top, the mushrooms are giving off water, and they have shrunk. Take the sheet out of the oven, and use a spoon to pick up and transfer the cooked mushrooms to another, dry sheet. Set the sheet aside to cool. Stick the next sheet into the oven, and repeat. Pack the mushrooms tightly on the cooking sheet.
Cover each sheet of cooked, repacked, and cooled mushrooms with aluminum foil, airtight, and refrigerate. Refrigerated, and slightly hardened, mushrooms travel better, and tightly packed mushrooms have less air surface, and will slide around less, so get less damage when traveling.
Just before serving, sprinkle the tops with just a bit of cheese, and broil for 5 - 10 minutes until the added cheese browns just slightly.