In a medium saucepan, whisk together 2 cups heavy cream, 1 cup whole milk, and half the ¾ cup granulated sugar over medium heat until warm (do not boil).
2 cups heavy cream, 1 cup whole milk, ¾ cup granulated sugar
In a separate bowl, whisk 5 large egg yolks with the remaining sugar until pale and thick.
Slowly stream the warm milk mixture into the yolks, whisking constantly to temper.
5 large egg yolks
Return the mixture to the saucepan and cook over low heat, stirring constantly, until it thickens enough to coat the back of a spoon. Remove from heat and stir in 1 tsp banana extract, 1 tsp vanilla extract, and Pinch of salt.
1 tsp banana extract, 1 tsp vanilla extract, Pinch of salt
Pour the custard into a bowl, cover, and chill in the refrigerator for at least 4 hours or overnight.
Attach the frozen KitchenAid ice cream bowl and churn the base for about 20–25 minutes until soft-serve consistency.
In the last 2–3 minutes of churning, add 1 cup crushed Nilla wafers and ½ cup white chocolate chips.
1 cup crushed Nilla wafers, ½ cup white chocolate chips
Transfer to a freezer-safe container, press parchment on top, and freeze for at least 4 hours for a scoopable texture.