Boil onions in lightly salted water to cover until just tender; drain well.
Remove centers from onions; chop fine.
Saute livers and bacon; chop fine.
Add sherry to white sauce; combine with mushrooms, chopped ingredients and bread crumbs.
Stuff onion shells with mixture; place in shallow greased casse- role.
Remaining stuffing may be spooned around on- ions.
Pour mushroom soup over onions.
Dot with butter; sprinkle with parsley.
Bake at 250 degrees for 1 hour.