Mrs. Stahl's Knishes
Board: Cooking Club at Recipelink.com
From: Meryl 12-14-2001
MSG ID: 0059251
MSG URL: http://www.recipelink.com/msgid/0059251
Also from one of the other boards it mentioned that the store closed but the recipe is still being used by another store. This information was posted in 2005, so I am not sure if the store is still selling knishes:

Bagel Supreme in Mill Basin
6220 Avenue U, between Mill and E 63rd Aves
718-209-9109

Good luck!