For appetizer-size pot pies, arrange 12 lightly greased 31/2-inch cast-iron skillets on an aluminum foil-lined baking sheet. Spoon a scant 1/2 cup of hot filling into each skillet. Cut puff pastry into 12 (approximately 4-inch) squares and lay 1 atop each skillet. Brush pastry with egg mixture, and cut slits in tops. Bake at 400° for 20 minutes or until pastry is golden brown.