1. Make simple syrup by adding water and sugar to a pot, then bring to a boil.
2. Allow to boil for one minute, then set aside to thicken.
3. Preheat oven to 350 degrees.
4. Sprinkle flour onto your counter top or work surface to keep pastry from sticking.
5. Unfold puff pastry sheets into two 8 by 8 inch squares.
6. Use a pizza cutter or sharp knife to cut each sheet into 4 squares.
7. Cut cream cheese length wise into 8 pieces.
8. Place one piece of cream cheese diagonally in the middle of each pastry square.
9. Place a similar sized piece of guava paste diagonally in the middle of the pastry squares, with the cream cheese.
10. Brush the edges of the squares with the beaten egg, then fold the upper half of the square over the filling, making a triangle.
11. Use a fork to crimp the edges and close the pastries.
12. Place pastries on a parchment lined baking sheet and bake 25-30 minutes, or until golden.
13. While they are baking, whisk together the powdered sugar, milk and vanilla to make the glaze.
14. Remove pastries from oven when done and allow to cool on cooling rack.
15. After placing on cooling rack, brush pastries with a think layer of the simple syrup, then drizzle with the glaze.
16. Serve warm or allow to cool, then serve.