Step 1: Combine 1 cup heavy cream, whole milk, 1/2 cup granulated sugar, vanilla bean seeds and pod, and salt in a medium saucepan. Heat over medium heat, stirring occasionally, until the mixture just begins to simmer around the edges. Do not boil. Remove from heat, cover, and let steep for 30 minutes to infuse the vanilla flavor.
Step 2: While the cream mixture steeps, whisk the egg yolks and remaining 1/4 cup granulated sugar in a separate medium bowl until pale yellow and slightly thickened.
Step 3: After steeping, remove the vanilla bean pod from the cream mixture. Slowly temper the egg yolks by gradually whisking about 1/2 cup of the hot cream mixture into the egg yolk mixture. Continue to whisk constantly as you slowly pour the tempered egg mixture back into the saucepan with the remaining cream.
Step 4: Return the saucepan to medium-low heat. Cook, stirring constantly with a wooden spoon or heatproof spatula, until the custard thickens enough to coat the back of the spoon (it should reach about 175-180°F or 79-82°C). Do not boil or the eggs will scramble.
Step 5: Immediately remove the custard from the heat and strain it through a fine-mesh sieve into a clean bowl. This ensures a silky smooth texture by catching any tiny bits of cooked egg or vanilla pod. Stir in the remaining 1 cup heavy cream and the optional vanilla extract.
Step 6: Cover the bowl with plastic wrap, pressing it directly onto the surface of the custard to prevent a skin from forming. Refrigerate for at least 4 hours, or preferably overnight, until thoroughly chilled. This chilling step is crucial for the best texture in home made ice cream recipes.
Step 7: Once thoroughly chilled, pour the mixture into your ice cream maker and churn according to the manufacturer's instructions. This typically takes 25-35 minutes, resulting in a soft-serve consistency.
Step 8: For a firmer ice cream, transfer the churned ice cream to an airtight container. Press a piece of parchment paper or plastic wrap directly onto the surface to prevent ice crystals, then freeze for at least 2-4 hours, or until firm. Enjoy your delicious home made ice cream!