Whip the whites of the eggs, with a pinch of salt added to them, to a very dry stiff froth. Beat to a cream the yolks and the sugar, then add the lemon. Fold in the beaten whites lightly (do not stir) and turn the mixture into a slightly oiled pudding-dish. If preferred, turn a part of it onto a flat dish, and with a knife shape it into a mound with a depression in the center. Put the rest into a pastry-bag, and press it out through a large tube, into lines and dots over the mound; sprinkle it with sugar and bake it in a very hot oven eight to ten minutes. Serve at once in the same dish in which it is baked. The flavor may be vanilla, or orange if preferred.