Custard: Heat cream, milk, and ½ cup sugar until steaming. Temper egg yolks with hot mixture, then cook to 175°F. Strain, add vanilla/salt, and chill 4+ hrs.
Raspberry Swirl: Blend berries, strain seeds (optional). Simmer with sugar/lemon juice for 5 mins. Cool.
Churn: Pour custard into ice cream maker. When almost set, add chocolate chunks.
Layer: Alternate ice cream and raspberry swirl in a container. Swirl gently with a knife.
Freeze: 4+ hrs until firm.
Notes
No ice cream maker? Use the no-churn method: Fold whipped cream into sweetened condensed milk + raspberry swirl.
Vegan option: Swap dairy for coconut cream and use vegan chocolate.
Boost flavor: Add 1 tsp balsamic vinegar to the raspberry swirl.