Line a cookie sheet with parchment paper or silicon mat. Remove the puff pastry from freezer.
Wash and clean the apples and cut into cubes. Place apple cubes in a bowl and toss with sugar. Mix well and let sit while Puff Pastry is defrosting.
Cut Pastry into 4 squares.
Whisk egg with a teaspoon of water. Brush over pastry edges, then add ¼ cup of the apple to a corner of the pastry square. Powder a little bit of ground cinnamon on top. Then fold pastry over to create a triangle.
Using a fork, pinch the seams closed. Coat with egg wash and sprinkle some sugar on top.
Bake for 20 – 25 minutes. Rotate pan if necessary half way though.
Allow to cool for 10 minutes and then serve to you hungry family!