It's actually quite easy to get to a post...use the basic Kitchen Seek page...
1. DESELECT the first checkbox that says "All Epicurious forums" (this finds too many results)
2. Toodle down to the bottom and SELECT both the Bon Appétit@Epicurious box and the Gourmet@Epicurious box (if you need both: you may know it was written in Bon Appetit and in that case, just select it.)
3. Go to the "SEARCH WHEN" fields.
3a. Change the year to one closer to what you're looking for...say Post "BEFORE" and "this date" =
01/01/01 (searches everything from forum start date to Dec 31, 2000). It doesn't like to find more than 200 at a time, so if that happens, narrow the date again.
4. Don't forget to put something in the FIND field. (you can even put your name there, but it needs to match whatever you used at the time)
5. To view an entire block of 100 threads: Remove the specific post number from the end of the address and let the .html come directly after the first-last thread range. See example:
http://63.123.232.200/HyperNews/get/archive_bon_appetit701-800.html
Note the only difference in each of these archive forums is the addition of the forum name before the post range.
By the way, you have to use this search page. If you go the regular epicurious.com site, they're only including the posts after 2004 (as you noted with utter frustration) and in a different format. (This tidbit of info is for anyone other than Nan reading this post.)
If these steps aren't clear, let me know and I'll try to explain it better.
PS: Sorry that I couldn't find the Louisiana cake you originally posted. If you remember any specific words entered in the post, it might help in the search.
http://63.123.232.200/HyperNews/get/archive_bon_appetit701-800.html