Break the eggs into an earthenware mixing bowl, and set the bowl in a pan of hot water.
Add the salt to the eggs, and beat the eggs with a Dover egg beater till they become light and stiff.
Beat the boiling water into the eggs and beat again till stiff.
Gradually beat in the sugar, adding it a little at a time, and beating well between the additions of sugar, and until the batter is stiff and light and nearly fills a one-and-one-half-quart bowl.
Beat in the lemon rind, oil, and caramel.
Now comes the most particular part of the making of the cake--the folding in of the flour.
It is easy, if care is not taken, to work out all the air that has been beaten into the batter, and the air is what is depended upon to make the cake light.
A flat wire whip is the best utensil to use in folding in the flour.
Sift a little of the flour over the top of the stiffly beaten batter.
Fold it in by dipping the whip edgewise down at the side of the bowl and lifting it up flatwise through the center.
When this flour is partly folded in, sift on more flour and fold it in the same way.
Continue folding flour in until all the flour has been used, but do not fold a stroke more than is necessary to get the flour completely blended with the batter.
Pour at once into a cake tin which has a piece of oiled paper fitted into the bottom.
Do not oil the sides of the tin.
Bake in a moderate oven till a broom straw run into the cake comes out clean.
When the cake is taken from the oven, turn it upside down to cool in the tin, placing something under the edge of the tin so that air can circulate under it.
Then if the cake falls, it will fall upward and be lighter.
When the cake is cool, it can be removed from the tin by running a knife around the sides of the cake.
Frost with icing made by stirring powdered sugar into beaten egg white or cream and coloring it with a few drops of caramel.
Decorate the top with pecan halves.