When I saw this question today
There are at least two duplicates, which are already (non-closed) duplicates of each other:
How do I get my chocolate chip cookies to turn out thick and soft?
How can I get chewy chocolate chip cookies?
Is there some mechanism for merging the two duplicates? Or do we just pick one and vote to close the other?
Moderators can merge questions, although typically we only do so when the following apply:
Question A is closed as a duplicate of Question B.
Question A really does look like an exact duplicate of Question B - as in, all of the answers that have been or ever could be submitted for A also apply to B.
Question A has at least one well-written or interesting answer which is not already covered (or is poorly covered) by the answers to B.
If you see a new question that's a duplicate of an old question, voting to close usually covers it - most of the time, the question will get closed before any answers get posted - or at least any answers worth keeping. In that case, merging is fairly pointless; the closure message already has a link pointing to the original question.
If you see an old question that you think fits all the criteria above, feel free to flag it for moderator attention and request a merge.
Speaking for myself only, I tend to give more weight to merge requests which attempt to explain why the merge would be useful vs. just deleting the dupe, e.g. "XYZ's answer addresses explains the BFF process and got 20 more votes than anything on the old question." It's not a requirement, but it helps grease the wheels.
It's very, very rare for a moderator to merge questions that have only been recently closed, and almost unheard of to merge questions that are still open (I'm not even sure if it's allowed). That's because its dupe status may still be in dispute at that point, and merges can't be undone like closures can. So don't be too surprised if a request to merge an open or just-closed question gets ignored for a while.
