Can Nigella's Victoria Sponge mixture be used to make mini Victoria sponges?
Nigella's Victoria Sponge cake uses the classic ratios of eggs/sugar/flour/butter. However, the flour is a combination of plain (all-purpose) flour and cornflour (cornstarch), as this combination gives the baked sponge a fine texture and a soft crumb. Baking powder is needed, to help the cake to rise, and a little extra is added if making the cake with the food processor method, as less air is incorporated during mixing, meaning the cake batter needs a little extra help to rise.
There would be no particular reason why the batter could not be used to make mini sponges. If you are using a mini Victoria sponge pan (which looks a little like a muffin pan but the cups in the pan have straighter sides) to make 6-7cm diameter cakes, then you should get approximately 16 sponges, to make 8 mini cakes once sandwiched. They should take 15-20 minutes to bake. The amount of filling in the recipe should be enough to fill the 8 mini cakes.