Cut the dark chocolate and milk chocolate into flakes.
When they are finely chopped, put everything in a large and capacious saucepan.
Add the liquid cream and mix well. Put the saucepan on a stove and, over low heat, let the chocolate melt well, eliminating any kind of residue or lumps.
After melting all the chocolate, you will get a ganache.
Add the rum and mix well until everything is incorporated. Put this mixture in a container and refrigerate for at least 2 hours.