Break the chocolate into pieces and melt in a double boiler, or in a heat-proof bowl over a saucepan of simmering water.
Puree the cherries in a blender with the olive oil, then stir the mixture into the melted chocolate. Set aside.
Whisk the egg whites with a pinch of salt at high speed until soft peaks form (about 3 minutes).
In a separate large bowl, whisk the egg yolks with the sugar and remaining 1/4 tsp salt until pale and creamy and doubled in volume. If your arms are strong and you're whisking quickly, this will take 3 -4 minutes.
Fold the cooled chocolate mixture into the egg yolks, then gradually fold in the egg whisks until everything is fully incoporated.
Spoon into 125 ml ramekins or cups, cover and refrigerate for at least 2 hours before serving