Preheat oven top 400° F degrees.
Line a cookie sheet with partchment paper. Unfold one of puff pastry sheets and cut into 9 even squares.
Cut guava into thin slices and place one slice into each one of the pastry squares.
Unfold and cut the other pastry sheet into 9 squares as well, and used to cover the squares the guava paste. Use a fork to press firmly aroud the edges.
Brush a little bit of the whisked egg on top of the pastries for a nice golden colors.
Bake for 25 minutes or until golden brown.