Here are 2 recipes. The first one is from No Cholesterol Passover Recipe by Debra Wasserman and Charles Stahler and the second one is from The Low-fat Jewish Vegetarian Cookbook (same authors)
For the dough
1 1/2 cup Matzo Meal (or Whole Grain flour)
4 tbsp potato starch (I think this is optional)
1 1/3 cup water
Mix the above well, refrigerate for 15 minutes then form into 2 ball. Roll out (or flatten) to about 1/4 inch thick. and cut into 3" x 5" squares.
Filling
3 cup cooked and mashed potatoes
1 large onion, chopped and sautéed in water
1/4 tsp each paprika and pepper
Lay about 1 1/2 tbsp filling in each dough square. Fold in sides and pinch closed. Lay on non stick baking pan and bake at 400 degree until light brown
Here is a link to the second one. I would reduce the salt or leave it out.
http://www.fatfree.com/recipes/potatoes/potato-knishesWe used to make the first one, but have not made it in like 30 years when my daughter was much younger. We would just get Whole Wheat tortillas, cut them into appropriate size, fill with mashed potatoes (sautéed with onions, mushrooms, etc), or roll them burrito style) and bake. We would also substitute cooked kasha for the potato. Or we would just make these balls of mashed potatoes, cool them down, then roll them in whole wheat flour and then bake them.
In Health
Jeff