Add half of beaten egg; stir well. Stir in dates and pecans.
Combine remaining half of egg with 1 teaspoon water; set aside.
Roll each sheet of pastry into a 12" square on a lightly floured surface.
Cut each square into 9 (4") squares. Spoon 1 heaping tablespoon date mixture into center of each square; brush edges of pastry with egg mixture. Fold each square of pastry into a triangle; seal edges with a fork.
Brush top of each pastry with remaining egg mixture, and sprinkle with sugar.
Place pastries on an ungreased baking sheet.
Bake at 400 for 10 to 12 minutes or until puffed and golden.