Hi, I would like to make Nigella's Mother-In-Law's Madeira Cake but I do not have self-raising flour, only plain flour. I would like to know how many teaspoons of baking powder I should I add to the mixture to make the cake successfully. Thank you. Mary
Nigella's Mother-In-Law's Madeira Cake (from Domestic Goddess and on the Nigella website) uses self-raising flour but it is fairly easy to convert plain flour by adding baking powder to the plain flour. In her more recent books Nigella has moved to just using plain flour plus raising agents as it saves space to just keep one type of flour and also self-raising flour can go out of date if you don't use it reasonably promptly.
Nigella converts her flour by adding 2 teaspoons of baking powder to each 150g/6 ounces/1 cup plain flour. Sift or stir the flour before using, to make sure that the baking powder is well-distributed. Also make sure that you use a proper 5ml measuring teaspoon and use level teaspoons. It is also worth checking the use by date on the container of baking powder as if it is old it will not be as active and the cake may not rise as well.