Melt the chocolate in a double-boiler over hot, but not boiling water. Stir occasionally.

Take off burner and allow to cool completely.

In a separate bowl, whip the cream with the rum.

Fold a ¼ of the cream and rum mixture into the chocolate.

Fold in the remaining whipped cream into the chocolate mixture.

Add nuts if desired.

Spoon, do not pour, the mixture into a mold lined with wax paper or plastic wrap.

Chill to set (about 2 hours).