Beat together the egg yolks, cream 3 tablespoons confectioners' sugar, and cinnamon until smooth. Stir into the grated potatoes along with the raisins, and mix until well combined; then stir in the flour.
Beat the egg whites with salt until stiff. Gently fold into the potato mixture.
Heat oil to 350 degrees F (175 degrees C) in a deep fryer or electric skillet.
Fry the cookies by dropping heaping tablespoon-size dollops into the hot oil. Fry until golden brown on both sides, then drain on a paper towel-lined plate. Dust with confectioners' sugar.
