Thaw puff pastry for 40 minutes. Preheat oven to 400°F. While pastry is thawing cook the bacon in a heavy skillet, drain, allow to cool, then crumble into coarse pieces. Unfold pastry on lightly floured surface. Roll into an 18×9-inch rectangle. Cut into 18 (3-inch) squares. Press squares into 3-inch muffin cups that have been coated with cooking spray; set aside. In mixing bowl, stir together cheese and milk until smooth. Spoon a rounded teaspoonful into each pastry shell. Top with pieces of bacon and green onion. Bake for 15 minutes or until pastry is golden brown.
Yields 18 appetizers.
NOTE: Boursin is a rich, soft, uncured mild cheese that has been infused with garlic and herbs. It can often be found in the deli section of larger supermarkets.