apple or other fruits that you wanna throw out, just cut into slice/cubes then cook in a pot of sugar water.
if dont have fruits, use snickers bar also can.
adjust based on your preference.

then after boiling them until it's soft and sugar caramalises, wrap it with pastry skin stick into the oven.
Better to use white sugar instead of brown sugar because you wanna see when the sugar inside the mixture caramalises.
Brown sugar....everything also brown 

use flour to prevent pastry skin from sticking to each other and tray.
every 15-30 mins, open the oven to glaze it with leftover sugar water, egg white, or butter depending on what you have leftover and desired final flavour.

flip it if you want bottom also brown a bit if your oven only got heating element on top like mine.
Can use dedicated pastry skin or roti canai skin.
I used to use frozen roti canai because it's cheaper, but i find it harder to puff, resulting in more uncooked dough.