Time: 20 minutes + 2 hours refrigeration
Add chocolate and cream to a glass bowl and place over a pot of gently simmering water. With a metal spoon stir until the chocolate has melted. Remove from the heat and cool slightly.
In a mixer, whisk the egg white until soft peaks form. Add the sugar and whisk until stiff peaks form.
Add egg yolks to the chocolate, along with the coffee and mix to combine. Now mix in 1/3 of the egg whites into the chocolate mixture. Add the remaining egg whites and gently fold in to retain the light airy texture.
Pour into individual glasses and refrigerate until chilled. Just before serving garnish with pistachios.