Preheat oven to 180ºC/350ºF

Lightly spray your baking sheet with non-stick spray.

Roll out puff pastry (just a tiny bit).

Cut pastry into 6 long triangles (see video).

Smear a little butter on each triangle.

Mix together the cinnamon and sugar and sprinkle on a bit on each triangle.

Add an apple slice to the wider end of each triangle and roll up the pastry.

Whisk together the egg and water and then brush on the mixture on each croissant.

Bake for 20min.

Allow to cool and devour.