01 - Split the vanilla bean lengthwise and scrape out the seeds. Place the seeds and pod into a saucepan along with the milk and heavy cream. Warm over medium-low heat until the mixture begins to steam gently. Do not allow it to boil. Remove from heat and let steep for 15 minutes.
02 - In a mixing bowl, whisk the egg yolks and sugar together vigorously until the mixture turns pale yellow and falls in thick ribbons from the whisk.
03 - Remove the vanilla pod from the cream mixture. Gradually pour the warm liquid into the egg yolk mixture in a thin, steady stream while whisking continuously to prevent the eggs from scrambling.
04 - Return the combined mixture to the saucepan and place over low heat. Stir constantly with a wooden spoon, making sure to sweep the bottom and corners of the pan. Continue cooking until the custard thickens enough to coat the back of the spoon and reaches 175°F on an instant-read thermometer. Do not let it boil or the custard will curdle.
05 - Pour the custard through a fine-mesh sieve into a clean bowl. Allow it to cool to room temperature, then cover and refrigerate for at least 2 hours until completely chilled throughout.
06 - Pour the chilled custard into an ice cream maker and churn following the manufacturer's directions until it reaches a soft-serve consistency.
07 - Transfer the churned mixture to a freezer-safe container with a tight-fitting lid. Freeze for at least 3 hours until it sets to a scoopable firmness.
08 - Remove from the freezer and let the ice cream sit at room temperature for 5 to 10 minutes to soften slightly before scooping and serving.