Pour the espresso and sugar into a saucepan and stir until sugar has dissolved.
Stir in the cream and put the saucepan on a low heat.
While the cream mixture is gently heating up, pour 2 tsp water in a small bowl and sprinkle the gelatin on top of it, so that it's completely covered in water.
Let this rest for about 5 minutes, until gelatin has completely softened.
When the cream mixture is about to boil i.e. when it starts to bubble around the edges, take the saucepan off the heat.
Take 1/2 cup of cream mixture and mix into the softened gelatin and stir to dissolve completely.
Add this 1/2 cup cream back into the remaining cream in the saucepan and whisk to mix thoroughly.
Pour the mixture into moulds and let rest in fridge overnight, until set.
While ready to serve, dip the bottom of moulds into some just boiled water, one at a time, holding them there for 8 seconds.
Invert them onto serving plates. Drizzle with chocolate or caramel sauce.