Clean mushroom caps thoroughly. Remove sausage from casing (if necessary). Mix sausage and cream cheese together in bowl.
Bring chicken stock to a simmer. Soak mushroom caps in simmering stock for 10-12 minutes.
Fill soaked mushroom cap with sausage and cream cheese mixture.
Preheat oven to 400ºF. Place filled mushroom caps on nonstick baking sheet.
Bake for 12-15 minutes (or until sausage is golden brown). Remove from oven, serve and enjoy.