Put the cocoa powder and xylitol in a small pan, and gradually add the espresso and vanilla, stirring until the xylitol has dissolved. Bring the mixture to a gentle boil over a medium heat. Redsauce the heat and simmer for 6-8 minutes or until slightly thickened and syrupy. Remove from the heat and set aside to cool slightly.
Tip the oats into a medium pan and stir in the milk, cinnamon and a pinch of salt. Cook over a low-medium heat for 4-5 minutes, stirring until thick and creamy.
Divide the porridge between two bowls. Top with a drizzle of the mocha syrup and the ground hazelnuts.