Over the past year, we've managed to basically give her father a collection of them. He has at least 6 if memory serves correctly. This past weekend, among other goodies, I found two more mugs-- a mushroom and a tomato-- at the goodwill this past saturday. To my recollection (as well as Jasmin's) he does not yet have the Tomato. As for the Mushroom, he already has it, but Jasmin is keeping this one for herself.
I think these things are charming. In the beginning, I think the first mug we got for her father was a present for father's day. Over time though, we've sort of gotten in the habit of picking them up when we can, here and there, for her dad. As you may know, I have no qualms about gifting thrift, especially when it's a nice, well thought out gift.
These mugs crop up a lot at thrift stores. Not to the point that they're always there like with copies of The DaVinci Code, but I've seen them crop up quite a few times. I think they're really charming. For all my googling though, I still don't know much about them. On etsy these sell at varying prices. Sellers' best guesses date these mugs at the 70s, which was my gut feeling given the style of the illustrations.
The entire set, based on etsy listings, includes: scotch broth, mushroom, ox tail, split pea, clam chowder, tomato, chicken, and onion.
If you happen to have any info on these mugs, please let me know. I'm very curious about them.