Nana Zelda's Potato Knishes

Dough:
1/2 lb. unsalted butter
1/2 lb. cream cheese
2 c. flour

Cut butter and cheese into flour.  With hands, press dough into firm ball.  Wrap dough in wax paper or foil.  Place in freezer to chill.

Filling:
~ 3 lb. potatoes
~ 1 1/2 lb. onions
(or more or less potatoes and onions in similar proportions)
~ 1/4 lb. butter
1 or 2 eggs

Dice onions and cook in butter until soft and yellow.  Peel and cook potatoes until soft.  Mash potatoes, add cooked onions, 1-2 eggs, and salt and pepper to taste.

Cut off small piece of dough.  Roll into thin rectangle on well-floured board, adding more flour if necessary to keep from sticking.  Place potatoes along long edge and roll up as if for jelly roll.  Slice into knishes - continue until dough and potatoes are used up.  (Cool potatoes slightly before placing on dough.)

Bake at 425 F until brown (~25 minutes).  Can be frozen instead.