Dissolve the cornstarch in 50ml whole milk, leave to rest.
In a small saucepan over medium heat combine the leftover milk, the heavy cream, sugar, pinch of salt, malted milk powder, cocoa powder and chopped milk chocolate, bring to an almost boil, stir until the chocolate is fully dissolved, add the cornstarch milk and cook until thickened. Take off heat, add the cream cheese, stir until glossy and smooth. Cool to room temperature and transfer to the fridge overnight.
Freeze in your ice cream maker according to the manufacturer's instructions adding the chopped #KitKat fingers at the last couple of minutes of churning. Store in the freezer for at least 4 hours until set or spoon right away.