Preheat oven to 350 degrees. Butter shallow baking dish.
Arrange mushrooms in dish stemmed side down.
Melt ½ cup butter in small saucepan over low heat. Increase heat to medium-high, blend in flour and cook for 3 minutes, stirring constantly.
Combine half and half, stock, sherry and pepper and bring to a simmer.
Remove from heat and pour sauce evenly over mushrooms.
Bake for 20-25 minutes until mushrooms look tender.
Sprinkle with bread/cheese mixture and continue baking until cheese melts, approximately 5 minutes.
Remove from oven and sprinkle with parsley for garnish.
Serve hot.
