Split the vanilla bean: Slice it lengthwise and scrape the seeds. Add both seeds and pod to a saucepan with milk, cream, and a pinch of salt. Bring to a gentle simmer, then turn off the heat. Let steep for 15 minutes.
Make the custard base: In a bowl, whisk the egg yolks with sugar until pale and thick. Slowly pour in the warm milk mixture while whisking constantly (tempering the eggs so they don’t scramble!).
Cook the custard: Return everything to the saucepan. Cook over low heat, stirring with a spatula, until the mixture coats the back of the spoon (or reaches 170–175°F / 77–80°C).
Strain and chill: Strain through a fine mesh sieve into a clean bowl. Chill in the fridge for at least 4 hours or overnight. (Pro tip: place the bowl in an ice bath to speed things up.)
Churn: Pour into an ice cream maker and churn according to the manufacturer’s instructions. Mine takes about 20 minutes.
Freeze: Transfer to a container, cover with parchment directly on the surface, and freeze for 4–6 hours until scoopable.