Break the chocolate in its 10 blocks. Place 1 block at the one end of the samosa wrapper and start folding it. (If you want to learn how to fold a samosa, follow Nina’s guide here.) Break the egg in a cup and with a pastry brush, brush the samosa with some egg white and make sure there are no gaps where the melted chocolate can run out. Heat enough oil in a pan to deep fry and when the oil is hot, but not smoking, add the samosas and fry very quickly on both sides until they are a light golden brown in color. Remove from the oil with a slotted spoon and place on kitchen toweling to get rid of excess oil. Serve immediately with a dusting of icing sugar and a smooth espresso.