Place potatoes on a floured surface and form into a mound with an indentation in the center. Sprinkle about 1½ cups of the flour and the cornstarch around the outer edge of the mound. Crack eggs into the center. Using your hands, combine mixture until a soft dough forms. It should not be sticky, so add remaining ½ cup flour (or more) as needed. Don’t overwork. Divide dough into fourths. On a floured surface, roll each section of dough into a rope about ¾- inch thick. Cut ropes into half-inch pieces. Roll pieces over the tines of a fork or wooden gnocchi maker to create the traditional curl and ridges.