When you enter a query in Google Image Search, the results often come with a strip along the top suggesting refinements for your search. For example, searching for cake pulls up suggestions of "happy birthday", "chocolate", "wedding", etc.
What did I search for to get the suggestions at right? Each strip is from a separate search, and each search term was one word.
Solution
It wasn't easy to find search terms for which the suggestions are half food, half not food. Some other baked goods I thought would work but didn't: brownie (all results were food), blondie (none were food), napoleon (none were food).
Congratulations to yesterday's solvers 🥐Maddy, 🥐Charlie, 🥐Connor, 🥐Milo, 🥐Yana, 🥐Kalpana, 🥐Peter V., Peter M., Jacob C., 🥐Hazel, 🥐the Greggs, and 🥐Graham. (Croissants for getting all 3.) Thanks to everybody who made a guess!
Ten years later, Dr. Shapiro revived Puzzle of the Day at Proof School, writing each day's puzzle on a name tag. After 600 puzzles or so, he was just starting to feel normal about students reading his chest all the time when campus closed and the puzzle, like the rest of our lives, moved online. New puzzles are posted daily on school days.
Want to catch up on old PotDs? There's an archive currently containing puzzles from March to December 2020.