Light sugar syrup with a few drops of bitter almonds extract added
etc...
2: Make melt chocolate, stirring from time to time.
3: Once chocolate is melted, remove from bain-marie and prepare a cold bath, by putting ice cubes and some water in a high sided container big enough to take the chocolate bowl (as in the diagram).
4: Place chocolate bowl onto the water and ice cubes, and start to whip (watch out for the splashes).
5: Chocolate will froth quickly into Chantilly, stop while it's still slightly runny because it will firm up a little, even after you stop whipping.
6: You can now use it like this, or for another recipe, like with a forcing bag on small cakes, or making chocolate puff pastry, etc.
7: Chocolate Chantilly can be made with a gourmet whip, proceed as a Chantilly cream and see how to in this video.