
Line a loaf tin with cling film.
Separate the eggs, putting the whites in a very clean large glass or metal bowl, ready for whipping and the yolks in a smaller bowl.
Break the chocolate into pieces and melt over a bain marie with the butter.
Add the sugar and orange extract to the chocolate mixture and stir until it dissolves.
Whisk in the egg yolks ones at a time.
Whip the egg whites with an electric mixer or by hand until you reach the stiff peak stage.
Use a large metal spoon to fold in the egg whites carefully.
Pour the mixture into the loaf tin and cover the top with cling film.
Freeze for at least 6 hours before serving.