Upon arrival, place the knishes in the refrigerator for up to 5 days. To serve later, wrap the knishes individually with plastic wrap, and store in the freezer for up to 3 months. There is no need to thaw the knish before heating.
To serve, heat knishes in a microwave for 2 minutes or in a 350F oven covered with foil for 10 minutes or until warm. Remove the foil for the last few minutes for a crispy knish. Best enjoyed with some deli mustard!