Heat the 10% cream with the vanilla pod and bring to a boil.
Remove the pot from the heat, cover and let infuse for 15 minutes.
Scrape the vanilla pod to remove the seeds and mix them with the 10% cream

Beat the egg yolks, sugar, and cornstarch in a bowl until the mixture is thick and foamy.
Gradually pour in the hot cream, whisking constantly.
Return the mixture to the pot and cook over low heat, stirring constantly.
When the cream coats the spoon, transfer it to a bowl.
Let it cool to room temperature before refrigerating it until it’s very cold.

Beat the 35% cream until it forms whipped cream, then fold it into the custard.
Pour the mixture into the ice cream maker and churn according to the manufacturer’s instructions.
2 minutes before the end of the churning, add the brownie bits.