Mix riced potatoes with cream and shortening. Chill for 1 hour. Add sugar, salt and flour. Blend thoroughly. Take about 1/3 cup of mixture and form into 2 balls. Continue with remaining dough. Chill balls for 1 hour. On a lightly floured board roll each ball into a paper thin round about 5 inches in diameter. Cook on heated griddle over low heat until very light tan. Turn and cook on other side. Serve hot or cold. All Lefse - Sprinkle with hot water and let lay a while, then butter and sprinkle with sugar and cinnamon, fold and cut.