Finely chop the chocolate.
Place the sugar in a heavy saucepan. Cook it over medium-high heat, stirring just until the sugar has melted.
Continue cooking, swirling the pan often, until the sugar is a dark golden caramel. Remove the pan from the heat; carefully pour in the cream.
Return the pan to the heat and simmer, stirring, until the caramel has dissolved. Remove the pan from the heat; while hot, stir in the chocolate, peanut butter, salt, and vanilla.
Let this stand for about 5 minutes or until the chocolate and peanut butter have dissolved.
Transfer chis to a bowl and cool to room temperature. Cover the bowl with plastic wrap and chill it until firm, about 2 hours.
Use a small spoon to scoop out the truffles; form them into 1-inch balls. Roll the truffles in the peanuts; transfer them to a tray covered with waxed paper.
Chill them until they're firm, about 1 hour.
Store them in an airtight container for up to 2 weeks.