Delving into bioluminescence, I find I can order a bioluminenscence kit.
These: https://www.abcam.com/products/chip-kits/rubyglow-bacterial-assay-luminescent-ab189820.html are currently out of stock. This kit "provides an easy and quick method to detect and quantify bacterial cells based on ATP present in metabolically active cells. The kit contains a genetically engineered luciferase which generates very stable luminescent signals."
This was not on my list of needs, but now it's definitely on my list of wants.
There are cheaper kits for classrooms, which "Light up your students' understanding of bioluminescent organisms." Snort. From this: https://www.carolina.com/bacteria/bioluminescent-bacterium-kit/154750.pr The students get to put Vibrio fisheri on to photobacterial agar. Hmmm. So does something on the agar light up? No, the Vibrio fisheri does. "Vibrio fischeri is a bioluminescent, Gram-negative marine bacterium that can be found free living and in a mutualistic association with certain squids and fishes." Ok, now I am jealous. I want to be free living and in a mutualistic association with certain squids and fishes. I suppose we are in a mutualistic association with the probiotics in our system, maybe. Mine certainly seem to like junk food.
This looks like the same kit, different advertisement. Oh, it's the same company. Duh. In fact, all three are from the same company. There are other companies and other bacteria, though: https://www.the-odin.com/grow-bioluminescent-bacteria-kit/ uses an e. coli. Here is the protocol for that kit.
These are cool kits, but can you frost a cake with them? No, but bioluminescent cake turns this up: https://everythingmushrooms.com/product/panellus-stipticus-glow-in-the-dark-bioluminescent-mushroom-cake/. A mushroom "cake" that is bioluminescent. That too is fabulous.