Fashion help?

I am studying a letter written 1 February 1794, the subject of which, at this juncture, is the latest London fashions:

 …your Friend Mrs. Gosling has been obliged to put on the Cravat, but all Bows are left off, for the Ladies either a very full Muslin plain Stock with a larger Pudding, or the long cravats like your old one twisted round the neck & fastened behind: this moment Maria has made her appearance with the plain Stock but no pudding, she sais these are very comfortable no ends to treble [sic: trouble] her, we are really much entertained with her new appearance…

I am without my subscription to the OED at present, so my question is: What was a ‘pudding’? Any helpful hint would be appreciated! Pictures (illustrations) would be welcome.