Pour ice cold water on the engine and turbo. The extreme cooling will help too.
I also replace the oil after each drive because fresh oil makes a cooler engine and I do a coolant flush after every drive because new coolant is better for cooling.
Seriously though the cars are tested in extreme temperature areas and things get replaced or remanufactured depending on the results of those tests. So I believe the engineers have settled any long term heat issues with under the hood after shut down. I mean if you are racing it's good to cool off with hood open and the parking brake off and getting as much cooling in there as possible. But with everyday driving shut the car off and go enjoy your life and stop worrying. I mean in the end it's a VW Golf not a Ferrari Daytona you are driving.
well ive had my car for 5 years, never once popped the hood after driving, and im in az, and my plastic hasnt melted due to extreme heat, i also have the hood insulation, and drive as fast as i legally can every time i drive, very well engineered car
edit
maybe if i tracked it, id let it run a while before i shut it down