Reduce the Soda: Pour Dr Pepper into a saucepan and simmer over medium heat until reduced by half and syrupy. Cool completely.
Prepare the Base: In a bowl, whisk together heavy cream, whole milk, sugar (if using), vanilla extract, and the cooled Dr Pepper syrup.
Chill the Mixture: Cover and refrigerate the base for 4 hours or overnight.
Churn the Ice Cream: Pour the chilled base into your ice cream maker and churn until it reaches a soft-serve consistency.
Freeze to Set: Transfer the churned ice cream to a freezer-safe container. Press plastic wrap directly on the surface, seal, and freeze for at least 4–6 hours.
Serve and Enjoy: Scoop, top with whipped cream and cherries if desired, and enjoy your homemade Dr Pepper Ice Cream!