Dorothea Repps’ 1703 recipe for ‘Diet Cake’ demonstrates the changing use of language over time. We use the word ‘diet’ when taking about any food or drink stuffs we consume but something advertised as a ‘diet cake’ would now be taken to indicate its’ benefit in helping a person lose weight. Clearly, this was not the intention here, though looking at the instructions more closely, the cook was expected to devote a total of 2 ¾ hours to beating the ingredients - a good workout for the upper arms.
Take 8 eggs and beat them a quarter of an houre. Then take a pound and a quarter of Refined sugar finely beaten and seared, beat them together a quarter of an houre or more, then take a pound of the best flower and mingle them all together, and beat them 2 houres, then put in halfe an ounce of Aniseeds, and bake them upon a plate, Your Oven must be as hot as will bake a penny loaf.
It is possible to make a sponge cake using only sugar, eggs and flour (no butter or oil) and while modern instructions would be to beat the eggs and sugar well, the flour should be folded in lightly to give a light, fluffy sponge. Beating the mixture for 2 hours would result in a much harder, rubbery texture - this would have been much more of a loaf for slicing, than a cake as we know it.
The volume of ingredients required for Dorethea’s recipes points to batch baking, which was common up until very recent times. Heating a brick or cast-iron oven to the required temperature took time and valuable fuel, so it was more cost-effective to cook in large batches, particularly when baking for a large household. The requirement for seared sugar possibly relates to the need to remove any moisture from the sugar, as a result of damp conditions in the pantry.
By the early 18th century, technical advances meant that the refinement of wheat flour was more highly developed, though restricted by price to the upper classes – leaving the poor to flour made from rye or other unrefined grains. At the same time, many innovations in our culinary culture resulted from the importation of new foodstuffs and from the New World and the greater availability of refined sugar from the Carribean was of particular significance in the development of cake-making. At the beginning of the modern period, 1 kilogram of sugar was equivalent in price to 100 kilograms of wheat, however, sugar prices began to fall after the discovery of the Americas and sugar became much cheaper. With refined sugar and the ‘best’ flour listed amongst the ingredients for Dorothea’s Diet Cake, we can tell that her recipes were aimed at the richer pocket.
 Dorothea Repps’ manuscript (1703) can be found at the Wellcome Library http://search.wellcomelibrary.org/iii/encore/record/C__Rb18589294.
 EGO, Food And Drink, by Gunther Hirschfelder, Manuel Trummer.