Beat in cold potatoes, eggs, cooled milk, yeast, water, salt and lemon extract.4. Mix in flour, adding just enough to make a soft dough. Knead well.5. Place dough in greased bowl; cover and let rise in warm place until doubled in bulk. 6. Roll out dough to 1/2 inch thickness. Cut with a well-floured cutter.7. Let rise uncovered about 30 minutes. Deep fry in oil heated to 375° F. Drain on paper towel.
Glaze:
Gradually add enough boiling water to powdered sugar and vanilla to make thin glaze. Drizzle over doughnuts.