Preheat oven to 350ºF (180ºC).

Thaw puff pastry according to the instructions on the package.

Make an egg wash by beating the egg with the water in a small bowl.

Unfold the puff pastry and roll it out with a rolling pin on a flat floured surface. We want to stretch it out about 1 inch (2.5 cm) on all sides.

Cut the puff pastry into 4 big squares and place 1 tbsp of arequipe in the center of each one. Brush the edges with the egg wash and fold over to form a triangle. Press the edges with your fingertips to seal them. You can also seal them with a fork. Make a few cuts on top of each turnover with a knife. Brush them with the egg wash and then sprinkle with the sugar.

Place the turnovers on a cookie sheet covered with parchment paper and bake for about 20 minutes or until golden brown. Let them cool for a few minutes before serving.