In a small saucepan over medium heat combine the heavy cream, the leftover whole milk, malted milk powder, sugar, salt, stir, bring to an almost boil, add the chopped white chocolate, stir until fully dissolved. Add the cornstarch milk and cook constantly stirring until thickened. Take off heat, add the cream cheese, stir until smooth and combined. Cool to room temperature, then transfer into the fridge overnight.
Freeze in your ice cream maker according to the manufacturer's instructions adding the chopped white chocolate KitKat candy at the last couple of minutes of churning. Store in an airtight container or spoon right away.