Cut the chocolate into small pieces, so it will melt easily and faster.
Melt the chocolate slowly in a bowl over a hot water bath (the bowl should not touch the water), with the water simmering, not boiling.
Bring the chocolate to between 45ºC/113ºF and 50ºC/112ºF. Take the bowl off the simmering water bath.
Add solid chocolate to the melted chocolate. This chocolate will act as ice, cooling the melted chocolate down. A good amount to start with is about one-quarter of the amount that is in the bowl. Stir continuously, checking the temperature frequently.