Britpickers, help! (concerning cabbage, sprouts and the occult)

[Haggridd <jkusalavagemd@yahoo.com>]

I was rereading "Good Omens" by Terry Pratchett and Neil Gaiman and 
came across a passage as follows: "Nothing is more reassuring, 
nothing is more true to the comfortable spirit of English occultism, 
than the smell of Brussells sprouts cooking in the next room."  I 
immediately thought of Arabella Figg and the smell of cabbage (which 
is a veggie very close to sprouts).  Is there an accepted tradition 
of the smell of cabbage-- or Brussels Sprouts-- associated with the 
occult in England?  If so, why?  "Good Omens" is a satire, so I 
assume it is one of those tired old cliches that everybody knows.  
Help, please!

Haggridd