Add the gelatine and water to a small bowl and stir to combine. Allow the gelatine to soak up the water for a few minutes.
Add the cream, vanilla, caster sugar, espresso powder, and espresso to a medium saucepan set over low heat. Allow the sugar to dissolve while stirring occasionally with a rubber spatula, once the sugar has dissolved remove the panna cotta mixture from the heat. Do not boil.
Add the gelatine to the cream mixture and stir to combine, making sure all of the gelatine has dissolved.
Divide the panna cotta mixture between 4 panna cotta molds or glasses. Cover the tops of each mold with plastic wrap, and refrigerate to set overnight.
Add the caster sugar and espresso to a small saucepan set over medium heat, and allow the sugar to melt while stirring occasionally. Once melted, allow the mixture to thicken up as the liquid evaporates. Pour into a glass jar to cool slightly.
Remove the panna cotta glasses from the fridge, and pour a thin layer of the coffee syrup over the top of each panna cotta. Decorate with milk chocolate or dark chocolate shavings or an espresso bean, and serve with your favourite Italian biscuits.