250 g dark chocolate+ extra, to serve
125 ml light extra-virgin olive oil
100 g superfine sugar
4 eggs, separated
60 ml Cointreau or other orange liqueur
Melt the chocolate in a double boiler over barely simmering water, stirring occasionally, until smooth. Gradually pour in the oil, stirring to combine. Remove from the heat and set aside.
Beat the egg yolks and half the sugar in a medium bowl with an electric mixer on high speed until pale and thick. Gradually pour in the chocolate mixture and Cointreau, whisking until combined.
Beat the egg whites and remaining sugar in a small bowl with an electric mixer on high speed until soft peaks form. Add a large spoonful to the chocolate mixture and stir to combine. Gently fold in the remaining whites.
Spoon the mousse evenly into serving dishes. Cover and chill in the refrigerator for at least 3 hours, or until required. Top with the extra chocolate and serve.