In a medium saucepan, combine milk and heavy cream over medium heat. Split a vanilla bean lengthwise and scrape the seeds into the mixture, then add the bean pod. Stir occasionally for about 5-7 minutes until mixture begins to simmer.

In a separate bowl, whisk together egg yolks and granulated sugar until thick and pale, about 2-3 minutes.

Slowly temper the egg yolk mixture by whisking in the hot milk and cream. Return mixture to saucepan and cook over low heat for 5-7 minutes until thick enough to coat the back of a spoon.

Remove custard from heat and strain through a fine-mesh sieve into a bowl. Cool for 15 minutes then cover and refrigerate for at least 4 hours.

Melt granulated sugar in a saucepan over medium-low heat until deep amber color, about 8-10 minutes. Pour onto parchment-lined baking sheet and cool before chopping.

Churn the chilled custard in an ice cream maker until soft-serve consistency, about 20-25 minutes.

Fold in chopped caramel brittle into churned ice cream. Transfer to an airtight container and freeze for at least 6 hours.