Preheat oven to 350°.
Carefully pick over the crab to remove any cartilage and shell
fragments.
Melt 3 tablespoons of the butter in a saute pan. Add the onions
and saute over medium heat until translucent, about 3 minutes.
Add the flour and cook an additional 3 minutes. Then add the milk
and cook 5 to 6 minutes more, stirring, until thick and creamy.
Do not let the mixture scorch. Remove from heat.
Add the crab, salt cayenne pepper, and Parmesan cheese to
the pan and combine well. Stir in the bread crumbs and parsley.
At this point the mixture should be as thick as a stuffing. Allow
it to cool to room temperature.
Heat the remaining 2 tablespoons of butter in another saute pan,
and saute the mushroom caps until tender, about 3 minutes. While
the pan is still hot, pour in the sherry and carefully light it
with a match. Drain the caps and allow them to cool.
Mound 1 tablespoon of the stuffing in each mushroom cap, and sprinkle
them with the Gruyere cheese.
Place caps on a greased baking sheet and bake at 350 degrees for
10 minutes, until bubbling. Serve hot.
Makes 24 stuffed mushrooms.
Recipe adapted from "The Red Lion Inn Cookbook"