China Southern Airlines offers some good solution from Benelux to Hong Kong. Return flights from Amsterdam are now available from €358 incl. all taxes and checked luggage. The cheapest solution is available when travelling on weekdays (Monday to Thursday). You would have to accept a bit longer layover in Beijing on your way back so consider to book free stop-over and visit both cities at once..
If interested in this solution with China Southern Airlines please look for flights in travel period from March till 21st of June 2017. (Latest date of your return flight from Hong Kong). Blackout period from 31st of March till 30th of April. Promotion is running till 25th of February or valid until sold out..
Travel date samples
22. – 28.2.
7. – 22.3.
9. – 22.5.
16.5. – 5.6.
25.5. – 8.6.
Booking sample of cheap return flights from Amsterdam to Hong Kong from €358! In this case you would fly from The Netherlands to Hong Kong on 1st of May. Your return flight from Asia back to Europe would be two weeks later on 15th of May 2017.