Whip the heavy whipping cream with an electric mixer until it’s thick peaks form. Add in the sweetened condensed milk and horchata powder. Mix together and taste test. Add more flavoring if desired.
Transfer half the cream to a large freezer safe container. Add in some dulche de leche to the cream and gently swirl in. Top off with the remaining cream and add some more dulche de leche. Gently swirl in leaving a visible ribbon. Cover and freeze overnight (8-12 hours).
If desired, add in some extra cinnamon or nutmeg to the ice cream before freezing for a bolder flavor profile.