Fill a dome-shaped mold to the top with chocolate ice cream. Place in the freezer until semi-firm, about 20 minutes.
Scoop some ice cream out of the center to create a crater and fill with vanilla ice cream. Return to the freezer until semi-firm, about 20 minutes.
Scoop a smaller amount of vanilla ice cream out of the center of each dome and fill with raspberry sorbet.
Place the mold in the freezer for 6-8 hours or overnight, until very firm.
Unmold the chocolates onto a wire rack. Pour the melted dark chocolate on top and transfer the tartufos to a plate. Quickly return the tartufo to the freezer until ready to serve.
