If you want something really quick and are not concerned with the sugar content, you can make this filling in seconds with just 2 ingredients: Chocolate sauce and Icing sugar. You may need something like this if you are making a selection of chocolates very quickly and you need an extra filling. The chocolate sauce already contains sugar this filling could be 75% sugar - but you're only going to eat 1 or 2, I hope.

Squeeze out about 2 Tbsp chocolate sauce into a small bowl. Add 2 Tbsp icing sugar and mix. Add a little more of either ingredient if you want to adjust the consistency. This is ready to use straight away as a filling for your chocolates.