Heat the cream, in a small saucepan or in the microwave until it's hot and starts to bubble.
Place chocolate in a medium bowl and pour over the hot cream. Let stand for 5 minutes.
Add the salt and whisk until smooth, then cover with plastic wrap and refrigerate until cool and slightly firm, anywhere from 1 to 3 hours (different chocolates take different times to set back up after melting).
Notes
Use good quality chocolate that's around 54-55% Cocoa solids
The salt is to cut sweetness, but totally optional.
Boiling can cause a skin to form on cream so I recommend not boiling. Heating until just before boiling point will do.