Crumble the sponge cake into breadcrumbs using your hands. Melt half the chocolate in a water bath. Add the cinnamon and cloves and the vanilla, mixing until smooth.
Remove from the heat and add the sponge, syrup and walnuts. Mix well and mould the mixture into a roll shape. Place in the fridge to cool. When cooled, slice into 0.5 cm slices, then cut each slice in half, so you have crescents.
In a water bath, melt the rest of the chocolate. Dip the crescents into the chocolate and place them on baking paper to cool. Put back into the fridge to cool, and serve. \