Add White Chocolate Sauce to a drinking glass and then brew your espresso shots directly over the sauce. Stir the white chocolate sauce and espresso together until the sauce is fully dissolved.
Pour cold milk and ice into the cup, leaving room for the cold foam. Set the iced white mocha aside.
In a separate smaller cup, add in the cold foam ingredients: ube extract, milk, heavy cream. Froth the mixture together with a handheld milk frother until thick and creamy (about 15-30 seconds).
Pour the ube cold foam over the iced white mocha, and enjoy!