>>> I looked to see what Mrs Beeton has to say about "cupcakes".[...]
>>
>> As M. Lyle said, you're better off looking to see what someone like
>> Fanny Cradock has to say on the subject.
>
> I don't think Fanny was particularly known for her cakes. [...]

Fanny Cradock is hardly known at all to the Internet generation, it
appears. But nonetheless she and her recipes will be a better guide to
what constitutes a cake in a paper cake cup than Mrs Beeton is, given
that the paper liners don't appear to have become a mass-market item
until the 20th century.