Hi Ian,

If you haven't done you soup/broth test in your slow
cooker, in addition to your vegi's, toss in a dried
Chimayo (New Mexico Red) chili pepper. Break off the
end and pour out the seeds, or it will be very hot.

https://en.wikipedia.org/wiki/New_Mexico_chile

It is like adding MSG (flavor enhancer) without the
chemicals (excitotoxins) and the delayed headache.

-T