01In a small saucepan, place 1/2 cup heavy cream, bittersweet chocolate, and semi-sweet chocolate chips. Heat over medium-low heat until chocolate melts, stirring frequently. Remove from heat and set aside.
02In a medium saucepan over medium heat, heat half and half and milk until very hot but not boiling, stirring often. Remove from heat and set aside.
03In a small bowl, combine sugar and cocoa powder; set aside.
04Using a mixer with wire whisk attached, mix chocolate mixture, half and half mixture, and sugar/cocoa mixture, in a large bowl until well blended. Stir in remaining 1 1/2 cups heavy cream, vanilla, and salt. Cover and chill thoroughly, at least 8 hours.
05Assemble ice cream machine according to manufacturer’s instructions. Turn on the machine and slowly pour ice cream mixture into the unit. Continue on low speed for at least 20 minutes, or until desired consistency, adding chocolate chips during the last 2 minutes of churning.
06Serve immediately or freeze in an air-tight container.