Melt the butter in a skillet.
Add the apples, sugar and cinnamon.
Cover and cook, stirring occasionally, 4 or 5 minutes.
Remove from heat and cool a little.
Mix in the softened cream cheese, egg yolk and flour.
Unfold 1 pastry sheet and roll into a 12" square. Slice into 9 pieces, about 4" x 4"
Spoon 1 tbsp apple mixture on each square. Fold in half diagonally to form a triangle.
Press edges with fork to seal. Place on an ungreased baking sheet.
Whip egg white until frothy, then brush over the tops of the turnovers.
Bake at 400 for 14 to 15 minutes until golden brown.