Take two large Spanish onions, wash and skin and tie them to prevent
breaking. Put them into a saucepan over the fire, cover with boiling
water, cook until they can be pierced with a broom straw--from two to
three hours, according to size. When done, drain and carefully take out
the centers, leaving about a quarter of an inch for the shell. Have
ready a stuffing made from a quarter of a pound of mushrooms prepared as
before. Put these and the centers of the onions into a chopping bowl and
chop very fine. Cook them together until the moisture from the onions
has almost evaporated, then add a generous heaping tablespoonful of
butter, a tablespoonful of rich cream, and three heaping tablespoonfuls
of grated bread crumbs, salt and pepper to taste. Fill the onion shells
with this mixture, smooth the tops nicely, sprinkle with bread crumbs,
brush with egg and a little butter. Put in the oven and brown about ten
minutes, and serve with the following sauce: Rub a generous heaping
tablespoonful of butter and a heaping tablespoonful of flour together.
Put a small teacup of milk into a saucepan on the fire, when hot stir in
the butter and flour and a quarter of a pound of mushrooms prepared as
before and chopped very fine, season with salt and pepper to taste.
Place the onions on a platter and pour the sauce around them, garnish
with parsley and serve.