I'm still experimenting with this, but over the last few days I've been flinging Babybear's bowl into the freezer for about five or so minutes before I'm due to serve up our dinner. The idea is that it gets cold, so that when the hot food hits it everything cools down nicely so that we can all achieve Baby Led Weaning nirvana and EAT AT THE SAME TIME.
As it happens we use melamine dishes, a rather attractive Babar set that my mother brought back from France and an utterly scuzzy cheapoid set of 'Chinese' food bowls that I am slightly ashamed to own. Anyway it has worked so far, but I don't know about doing it with ceramic or plastic bowls. Feel free to conduct your own crockery tests and report back.

Post Script. My laziness knows no bounds, clearly... I've started leaving the dishes in the freezer all the time as I kept forgetting to put them in. It works brilliantly with the melamine ones (she says modestly).

You know that you can add them to ANYTHING that you want it to cool down quickly, don't you? Well, anything savoury, I suppose.