Often in restaurants and bars, the porn star martini has a fairly thick foam and is velvety to drink. having tried the above recipe i dont get this much foam. I have been using Giffard passion fruit liqueur instead of Passoa. Is that the reason? Can anyone advise on how to make the foam (without using eggs)?

Hi Fredie,
If you don't want to use an egg, you can try aquafaba.
Hope it works for you. Succes!