Roll 1 pastry sheet into 12-inch square on lightly floured surface; cut into 8 rounds with 3-inch cookie cutter. Repeat with remaining pastry sheet. Reserve trimmings for garnish.
Spoon about 1 tsp. guava paste onto center of each pastry round; top with 1 Singles piece. Brush edges of pastry with egg; fold in half. Seal edges with fork. Garnish with reserved pastry trimmings as desired; brush with egg.
Place on parchment-covered baking sheet.
Bake 15 min. or until golden brown.