Break the chocolate into pieces and place in a heat proof bowl. Melt it by placing the bowl over a pan of simmering water.
Separate the eggs so you have five egg yolks and five egg whites.
Whisk the egg whites until they hold soft peaks.
Mix the egg yolks into the melted chocolate along with the Baileys until you have a silky-smooth chocolate mixture.
Whisk in a quarter of the egg whites into the chocolate.
Gently fold the remaining egg whites through the chocolate one third at a time, using the figure of 8 technique to ensure you don't beat the air out of it.
Spoon the mixture into four glasses or ramekins and place into the fridge to chill for at least an hour.
Meanwhile, use an electric whisk to whip the double cream and vanilla bean paste until it holds gentle peaks. Be careful not to over whip it.
Fold through the icing sugar and a splash of Baileys.
Spoon the cream over the top of the mousses. Garnish with the chopped chocolate and any other garnish you fancy.
Serve.