In my experience, it’s still good a week after it’s made kept in a jar at room temp. I wish I could tell you exactly how long it’ll keep but to be sure that your friends will receive it fresh, make it a day or two before the event. Hope that helps :)

yes, I think the egg yolk makes it more silky and creamy, I have made yema before without the any yolks and it’s just not the same..
In my own experience ( not that I’m an expert on this), if you want a creamy yema, just reduce the cooking time, the longer you cook it the more dough-y it gets.. I hope that helps..thank you so much for visiting :)