I used unsalted matzo meal. :-) And really it was a mixture of schmalz and canola oil (didn't have enough schmaltz).
Last night, take two. Better, still not great.
Do you shred or puree the potato? Try doing a mix of both. I shred all of the potatoes in the cuisinart with the grating blade. Then squeeze the shreds in a dishtowel to get out as much water as possible. Then take 1/3 of the shreds, and puree them with the egg, onion, matzo meal, baking powder and salt. Mix the puree with the remaining shreds.
dinner last night:
potato, leek, and cauliflower soup made with chicken broth in the pot that the schmaltz and gribenes had cooked in, without washing the pot. I sauteed the onion and leek in the chicken fat that remained in the pot, and used the soup to deglaze the layer of crusty, oniony fond left in the bottom from the gribenes. Oh, and there was some napa cabbage in there, too. I pureed it with a hand blender. Wow, was that delicious soup. We ate it with some German 100% rye pumpernickel.