Put one pound of powdered sugar in a good-sized bowl, which stand in a bain-marie of hot water; sift one pound of flour upon a sheet of paper, then break twelve eggs into the bowl with the sugar, which whisk rather quickly until they become a little warm and rather thickish, then take the bowl from the bain-marie, and continue whisking until nearly or quite cold ; then add the chopped rind of a lemon and the flour, which mix lightly with a wooden spoon; have ready your mould or baking-dish lightly buttered, into which you have put a little flour, knocking out all that does not adhere to the butter, pour in the mixture and place it one hour in a moderate oven, it may require longer or not so long, but that will depend entirely upon the compass you have it in; if done it will feel firm to the touch, but the surest method is to run a thin wooden skewer into the centre, if it comes out clean the cake is done, but if not some of the mixture would adhere to it; care should be taken not to disturb it until quite set, or it would sink in the centre, and never properly bake; when done turn it out upon a sieve to cool. Serve where indicated.