In a small bowl stir together cream cheese, confectioners sugar, and vanilla until smooth. Peel, halve, and core apples and cut into 1/4-inch slices. In a bowl toss apples with 2 tablespoons granulated sugar. Preheat oven to 375F. On a lightly floured surface roll 1 sheet puff pastry into a 15- by 11-inch rectangle. From a long side, cut four 1/3-inch-wide strips. From a short side, cut two 1/3-inch-wide strips. Set pastry strips aside. Halve lengthwise what remains of rectangle and put halves on a baking sheet. Just inside pastry rectangles edges, brush 1/3-inch-wide borders of egg wash, reserving remaining egg wash. Arrange pastry strips on borders so that they are flush with edges of rectangles, trimming strips to fit. Spread cream-cheese mixture inside borders on rectangles and top with apples. On a lightly floured surface roll remaining puff-pastry sheet into a 14- by 10-inch rectangle and halve lengthwise. Cut several 2 1/2-inch diagonal slits down middle of each rectangle (do not cut within 1 inch of edges). Brush pastry borders of apple-topped tarts with some remaining egg wash and top each with 1 pastry rectangle. Press edges gently but firmly together to seal. Brush remaining egg wash over pastry tops and sprinkle with remaining 2 tablespoons sugar. Bake tarts in middle of oven 30 minutes, or until puffed and golden. In a small saucepan simmer maple syrup 10 minutes, or until reduced to about 1/3 cup. Brush hot syrup glaze over warm tarts. Serve tarts warm or at room temperature. Makes two 14- by 5-inch tarts. Gourmet October 1994