Soak the gelatine in a bowl of cold water.
Pour the milk and cream into a saucepan and bring
to the boil, then remove from the heat.
Whisk together the egg yolks and caster sugar in
a bowl. Pour the hot cream mixture over the beaten eggs
and sugar. Transfer back to the saucepan, return to a low heat and stir until slightly thickened. Remove from the heat and set aside.
Break the chocolate into a bowl. Pour half of the
warm cream mixture over the chocolate and stir to combine.
Remove the gelatine from the water and squeeze to
remove the excess liquid. Add the gelatine to the remaining warm cream mixture in the saucepan, then pour into the melted chocolate. To finish, stir in
the orange zest.
Pour into individual ramekins and leave to set for at least 2 hours in the refrigerator.