How to prepare:

1. In a small saucepan, place 1/2 cup of the whipping cream, semisweet chocolate, and unsweetened chocolate. Melt together over low heat until chocolate is completely melted, stirring frequently. Remove from heat and set aside.

2. In a medium saucepan over medium heat, heat half and half until very hot but not boiling, stirring often. Remove from heat and set aside.

3. In a small bowl, combine sugar and cocoa powder; set aside.

4. In a large bowl, gradually add the cocoa mixture to the egg yolks, whisking until well blended and slightly thickened. Gradually add the melted chocolate mixture and the heated half and half, whisking to combine.

5. Return mixture to medium saucepan and cook over medium heat until small bubbles form around the edge and the mixture is steamy, stirring frequently. Check for doneness by dipping a silicone spatula in the mixture to coat it entirely, then run a finger through the mixture (wait until it's cool enough to touch). If the line holds, it's ready.

6. Transfer mixture to a large bowl and stir in remaining whipping cream, along with the vanilla and salt. Cover with plastic wrap and chill in the fridge for 8 hours or overnight.

7. When ice cream is thoroughly chilled, it's time to churn it.

With an Ice Cream Maker:

Follow the manufacturer's instructions to churn the ice cream. Once churned, fold in the chopped chocolate or chocolate chips, then transfer to an airtight container and store in the freezer.

Without an Ice Cream Maker:

Pour the chilled mixture into a large shallow pan, such as a 9x13" baking pan. Place in the freezer for 30 minutes, then remove and beat the mixture to incorporate the frozen bits. Return to the freezer, then take out and repeat the process after another 30 minutes, folding in the chopped chocolate or chocolate chips after you do so. Continue to freeze and churn every 30 minutes or so, until the ice cream is too stiff to beat, then transfer to an airtight container and store in the freezer.