Create a double boiler – which is a pot, half filled with simmering water with either a metal or glass bowl snugly fit on top to create a constant source of low to moderate heat – perfect for melting chocolate.
To the bowl, add the eggs and sugar, then whisk vigorously until the sugar is melted and the eggs are becoming pale and fluffy.
Transfer to a stand mixer and whisk on high for 4-5 minutes (alternatively, you can whisk by hand off the heat for 10 minutes).
Whilst the eggs are whisking, place the chocolate in a double boiler with the espresso and stir with a spatula until it is melted.
Take the chocolate and espresso mixture off the heat and let rest for 3 minutes, then gently fold until the fluffy eggs.
Once that is done, whisk the cream until soft peaks form, then gently fold that into the rest of the mixture.
Transfer into your preferred eating vessel, wrap with cling film and refrigerate for at least 2 hours before serving.
Serve with some grated chocolate and toasted hazelnuts.
