Edit: 13:00hrs GMT. The deal is now gone, sorry!
Cathay Pacific have got one of the best (legitimate!) First Class fares I think I have ever seen. Starting from Portugal, (Porto, Lisbon or Faro) you can fly to several Asian cities from around €1300 one way in first class. There is wide open availability until the end of 2019.
The cheapest fares are to Hong Kong starting at around €1315. Since Cathay Pacific do not fly directly between Hong Kong and Portugal you will need to transfer in one of London, Zurich or Frankfurt. The journey between Portugal and your intermediate transfer point will be in business class.
I flew Cathay Pacific's First Class on their Boeing 777 about two and a half years ago, although as I explained in this interview with Million Mile Secrets, I wasn't really in the frame of mind to be taking lots of pictures. So instead here are some media-approved images.
If crediting the air miles to British Airways Executive Club then the obvious solution is to fly British Airways between Lisbon and London Heathrow which arrives at Terminal 3 so there is no airport nor terminal swapping which Porto and Faro would require. The Cathay Pacific lounge at Heathrow was only renovated in the last couple of years too, and if you are interested in plane spotting then try to bag yourself ‘The Throne' which is the corner seat where the lady is sitting below.
If you are flying further afield than Hong Kong then I highly recommend visiting Cathay's The Pier First Class Lounge near Gate 64 which has sleeping rooms, a full-service restaurant facility and massage area. By far my favourite anywhere in the world!
The fare was not bookable on Cathay Pacific's website when I tried, although you are welcome to try if you wish. If that does not work, you will need to go via an Online Travel Agency such as Skyscanner. (Don't forget to change the currency to match your payment method).
Below I have put some screenshots of fares that I could find to various cities.
To Hong Kong: