Preheat the oven to 200°C (392°F).
Flour a flat surface. Lay the puff pastry on this surface.
Flour the top of the pastry and roll it out until thin.
Using a cookie cutter or any circular object, cut out 20 to 24 circles and brush the edges of each circle with the egg.
In the center of each circle, place 1 slice of guava paste, 1 slice of cheese, and ½ tablespoon of dulce de leche.
Place another circle on top to encase the filling.
Seal the edges using your fingers. Repeat the process with all cakes.
Place the cakes on a tray lined with parchment paper.
Bake for about 20 minutes or until golden brown.
Once baked, remove from the oven and sprinkle with granulated sugar.
Allow the cakes to cool slightly, then serve warm or at room temperature.