How to format an Eval/Grouped By timestamp?

I have a timestamp value that I use in both Joined tables through the Eval capability as well as in the Grouped By of Aggregated output.

I would like to be able to Format the timestamp into a human readable format, but I am not finding the format timestamp filter.

How can this be accomplished without creating a new column in the database (for a formatted timestamp) or by looping through the list of items to create a formatted version of the timestamp?

Thanks!