Make a well in the center. Beat the buttermilk with the egg and pour into the well, stirring together until a light spongy dough forms that is just firm enough to handle. Do not overwork the dough ...

However, celebrity chef Ina Garten, who is no stranger to potato dishes, has a secret ingredient you might not have thought to use — buttermilk. Buttermilk should not be confused with regular ...