Hello Cindyb,
I grew up with Niffl"i"es. If you google Nifflies with the "I" you will find some hits.
My grandparents were Slovak (grandmother near Vienna), and she make Nifflies often.
As you know from others, they can be make a day before, and they will be delicious.
(Just don't cook them too long, or they will be a bit tough).
Bellevue20 (central Michigan)