MmeLindt, I just had my sister on the phone (BTW she owns a B&B in Le Bouveret if you ha ve family comming over to visit [cheeky emoticon]) She says I am all mixed up with my chocolate and the ones with "graisse de coco are the fondants au chocolat that people make arround Christmas time! Maybe you had the joy of sampleing them?
Her recipe for rochers au chocolat is this one:
300/400 gr chocolat (you can mix "au lait" "noir" ou "blanc" to taste)
1 tblsp of butter
1 sachet of "sucre vanille" (vanilla sugar)(not if you make them with white choc!)
melt in a bain-marie
Add cornflakes (flakes shoud all be nicely covered but not dripping with chocolate IYSWIM)
With two tea spoons shape into little rocks and put in fridge to harden. she sprinkles the dark ones with icing sugar and the "chocolat blanc" ones with cocoa powder!