Place about 3/4 of the chocolate into a heatproof bowl, and place over the top of a pan of gently simmering water. Heat, stirring occasionally until the chocolate has melted, then continue to heat the chocolate to 43 degrees C, stirring occasionally. (You may use a meat thermometer if your sugar thermometer does not go that low.)

As soon as the melted chocolate reaches temperature, remove from the heat, and stir in the remaining chopped chocolate until melted. Continue stirring until the chocolate has cooled to 32 degrees C.