In a medium heavy-bottomed saucepan, combine the heavy cream, whole milk, half the sugar (6 tablespoons), the vanilla bean pod and scraped seeds, and salt. Heat over medium heat, stirring occasionally, until the mixture just begins to steam and small bubbles form around the edges — do not boil. Remove from heat.

In a medium bowl, whisk together the egg yolks and remaining sugar (6 tablespoons) until the mixture is pale yellow and slightly thickened, about 2 minutes.

Temper the eggs: very slowly pour about 1/2 cup of the hot cream mixture into the yolks, one tablespoon at a time at first, whisking constantly. Once the yolks are warmed, pour in the remaining cream mixture in a slow, steady stream while continuing to whisk.

Return the combined mixture to the saucepan. Cook over medium-low heat, stirring constantly with a wooden spoon or heat-safe spatula, until the custard thickens enough to coat the back of the spoon and reaches 170–175°F on an instant-read thermometer, about 8–10 minutes. Do not let it boil.

Remove from heat and pour the custard through a fine-mesh strainer into a clean bowl, discarding the vanilla pod. Stir in the vanilla extract. Set the bowl over an ice bath and stir occasionally until the custard cools to room temperature.

Cover the cooled custard with plastic wrap pressed directly against the surface and refrigerate for at least 4 hours, or overnight (strongly preferred) until thoroughly chilled to 40°F or below.

Pour the chilled custard into your ice cream maker and churn according to the manufacturer's instructions, typically 20–25 minutes, until the ice cream reaches a thick, soft-serve consistency.

Transfer the churned ice cream to a loaf pan or airtight container. Press plastic wrap directly against the surface and freeze for a minimum of 4 hours, or until firm and scoopable.

Before serving, let the ice cream sit at room temperature for 5 minutes for the easiest scooping. Serve in bowls or cones and enjoy immediately.