Potato Knish

Toast

have used egg white, egg yolk and butter...my knishes wont brown!

You paint the puff pastry dough or fillo dough with the same schmaltz with which you seasoned the mashed potatoes.  They brown up like a picture.  We make about 60 for each night of the Rosh Hashanah evenings.  Everybody takes 2 or 3 if there are enough.