Cut stems from mushrooms; finely chop enough stems to measure
1/4 cup. Heat butter in 10" skillet just until bubbly. Place
mushroom caps, topsides down, in butter. Cook uncovered until
mushrooms are light brown; remove mushrooms with slotted spoon.
Cook and stir onion in same skillet until tender; stir in wine.
Simmer uncovered 2 minutes. Mix in chopped mushroom stems and
remaining ingredients except cheese and mushroom caps; cool
slightly. Shape mixture into 24 small balls; place 1 in each
mushroom cap. Sprinkle with cheese. Set oven control to broil.
Place mushroom caps on rack in broiler pan. Broil with tops 3 to 4"
from heat until cheese is melted, about 3 minutes.
