Plantain were not ready to puree, can they be saved?
Assuming that you're making Empanadas de Plátano Maduro, You can't really "save" them.

In the course of ripening, plantains convert starches to sugars.  This change also changes the structure of the plantain flesh, from firm to soft &amp; sticky.  This isn't a small conversion, it's a change in like 20% of the plantain flesh.  Nothing you can do is going to substitute for that sticky, ripe-plantain texture, and I can't find any verified way to make them ripen once you've peeled and cooked them.  Sorry!