If using frozen berries, let them thaw completely. Blend the raspberries until smooth, then strain through a fine-mesh sieve to remove the seeds. You should have about ½ cup purée. Set aside (this can be made ahead and chilled).

In a medium bowl, whisk together the egg yolks and sugar until pale and slightly thickened.

Combine the milk and cream in a small saucepan and gently heat over medium-low until warm but not boiling.

Slowly whisk a small amount of the warm dairy into the egg mixture to temper, then pour the egg mixture back into the saucepan. Cook gently, stirring constantly, until the custard thickens enough to coat the back of a spoon, or reaches about 170°F on an instant-read thermometer.

Strain the custard directly into the bowl of raspberry purée. Add the vanilla and salt and stir to combine. Press plastic wrap directly onto the surface and refrigerate for 8 hours or overnight.

Churn the chilled base in an ice cream maker according to the manufacturer’s instructions. During the final minute of churning, add the frozen chocolate shards.

Transfer to a container, cover, and freeze until firm.