Roughly chop three quarters of your chocolate on a chopping board (half centimetre or quarter inch cubes are perfect).

Finely chop the remaining quarter.

Place the roughly chopped chocolate into a bain-marie (a glass bowl placed on a saucepan half filled with water), making sure that the bowl does not touch the water. Slowly heat the water, ensuring that it does not boil. Stir regularly using a flexible spatula so that the chocolate melts nice and smoothly.

Check the temperature with a thermometer. When it reaches 55°C-58°C (131°F-136°F) for dark chocolate, or 45°C- 50°C (113°F-122°F) for milk or white chocolate, remove the bowl from the saucepan.

Set aside one-third of the melted chocolate in a bowl, in a warm place.

With the remaining two thirds of the melted chocolate, add the finely chopped chocolate and stir it constantly. This brings the temperature down to the desired level. The dark chocolate should reach a temperature of 28°C-29°C (82°F-84°F); milk chocolate should reach 27°C-28°C (81°F-82°F); and white chocolate should reach 26°C-27°C (79°F-81°F).

Finally, add the melted chocolate that you have set aside to increase the temperature again. The dark chocolate should now reach 31°C-32°C (88°F-90°F); milk chocolate should reach 29°C-30°C (84°F-86°F); and white chocolate should reach 28°C-29°C (82°F-84°F). Keep stirring until the right temperature is reached.