01 - Combine mashed ube, granulated sugar, coconut milk, ube extract, and salt in a saucepan. Cook over medium heat, stirring constantly, until the mixture is smooth and slightly thickened, about 5 minutes. Remove from heat and allow to cool to room temperature.
02 - In a blender, blend unsalted shelled pistachios, whole milk, heavy cream, honey or sugar, vanilla extract, and salt until smooth. Transfer the mixture to a saucepan and heat gently over medium-low, stirring frequently for 5 minutes without boiling. Remove from heat and let the mixture cool.
03 - Pour the cooled ube mixture evenly into ice cream bar molds, filling each mold halfway. Freeze for 1 hour so the layer sets sufficiently for the next addition.
04 - Pour the pistachio mixture over the set ube layer, filling molds to the top. Insert sticks and freeze for at least 5 hours, or until completely solid.
05 - Remove bars from molds. For garnish, drizzle with sweetened condensed milk and sprinkle with chopped pistachios if desired.