Melt Chocolate: In the top bowl of a double boiler over simmering water, add 1/2 cup white chocolate chips and 1/2 cup heavy whipping cream. Whisk as the chocolate melts until the mixture is smooth.
Add Dulce de Leche: Stir in 1/3 cup dulce de leche. Continue whisking until smooth and fully combined. Remove from heat and let cool to room temperature.
Blend Frappuccino: In a high-powered blender, add 1/2 cup toasted white chocolate syrup, 1 cup whole milk, 2 shots espresso, and 3 cups ice. Blend until thick and smooth.
Serve: Pour into 2 large glasses. Top each with Whipped cream and a sprinkle of Red sanding sugar crystals. Serve immediately.
Notes
Make-Ahead Tips: The toasted white chocolate syrup can be made up to 3 days in advance. Store in a covered jar in the refrigerator and rewarm gently before using.Storage: Frappuccinos are best enjoyed fresh, but leftover syrup keeps well chilled.Shortcut: Use a store-bought white chocolate syrup and add 1 tablespoon dulce de leche directly to the blender for that toasted flavor.Optional Sweetness Boost: Add 1 pump (about 1 tablespoon) vanilla syrup for a classic Starbucks touch.Hot Version: Add ΒΌ cup toasted white chocolate syrup to each mug. Pour in espresso, top with steamed milk, and finish with whipped cream and sanding sugar.