Hi, I want to make Nigella's Chocolate Guinness cake for at least 30 people. How do I change the measurements?
Nigella's Chocolate Guinness Cake (from Feast and on the Nigella website) will serve about 12 people. Scaling the cake up to serve 30 would be very difficult, partly as very large cakes can be difficult to bake in domestic ovens. Scaling cakes generally can be a little tricky and unfortunately is not something we are able provide advice for with most of Nigella's cakes.
We would suggest instead making 3 separate cakes. The cake will keep in an airtight container, without icing, for up to 5 days. The cake also freezes very well if un-iced so it would be possible to start making the cakes well in advance. To freeze a cake let it cool completely on a wire rack then wrap it tightly in a double layer of clingfilm (plastic wrap) and a layer of foil. Freeze for up to 3 months. To thaw the cake, or cakes, unwrap and put on a wire rack. Leave at room temperature for 3 to 4 hours. Ice the cakes just before serving.