B., so funny to have read this request today! I just sent an email to a handful of girlfriends to ask the same question about my 9 month old daughter. Here are the responses I got and the information from my attempts):
pea size pieces of cheese (I used pre-cubed cheddar cheese and then picked off little specks, smooshed them into my fingers, and then put them on the high chair tray. Worked out great!)
toast (I had 12 grain bread, so couldn't give that to her, so I used an English muffin. toasted it lightly, then peeled off little pea size bits from the soft bread part- didn't touch the crust)
Crumbled up hard boiled egg YOLK (I haven't tried it yet)
Steamed carrots- super soft, then broken up (I haven't tried it yet)
Good luck to you! If you have a good experience with the latter of the 2, let me know!