Make the Custard Base: Mix the heavy cream, whole milk, and sugar in a medium saucepan. Pour the mixture into a saucepan and heat over medium heat, stirring occasionally until hot and the sugar is dissolved. Do not let it boil.
Whisk the Egg Yolks: In another bowl, lightly whisk the egg yolks until pale yellow and thick. Then, while whisking the egg yolks constantly, use a spoon to slowly drizzle in about ½ cup of the hot cream mixture.
Combine the Mixtures: Now we slowly add the tempered egg yolk mixture to the pan with the rest of the hot cream mixture, whisking constantly. Keep cooking on medium heat until it thickens and the temperature registers about 170F (77C) or coats the back of a spoon.
Strain the Custard: Strain the custard through a fine-mesh sieve into a clean bowl to remove any bits of cooked egg. Let cool to room temp, then cover and refrigerate for at least 4 hours or overnight for best results.
Churn the Ice Cream: Chill the custard and pour it into an ice cream machine, following your manufacturer's instructions. Churn for 20-25 minutes until thickened and has a soft-serve texture.
Fold in the Cookies: Once the ice cream is churned, gently fold the coarsely chopped chocolate sandwich cookies into the finished ice cream. Just take care not to crumble the cookies tightly, and you want big chunks of cookies all around.
Freeze the Ice Cream: Pour the mixture into a sealed container– preferably airtight- and stick- and place in the freezer for about four hours or until it becomes solid. Scoot is op and serves when ready!
