Place egg whites in a small bowl; let stand at room temperature for 30 minutes.
Meanwhile, in a large bowl, combine the flour, baking powder and salt. Combine the egg yolks, sugar, water, butter, lemon zest, vanilla and, if desired, brandy; stir into dry ingredients just until combined. Beat egg whites on medium speed until soft peaks form; fold into batter.
In a cast-iron or electric skillet, heat oil to 375°. Drop batter by teaspoonfuls, a few at a time, into hot oil. Fry until golden brown, about 1-1/2 minutes on each side. Drain on paper towels. Dust with confectioners' sugar. Serve warm.