I was a cafeteria lady. I promise you, no one cares if you mention specific people. I totally understood that as a cafeteria lady, I had zero impact on those kids' lives and never expected special recognition. Hearing "thanks everyone, but especially thank you to Mr. Larlo" wouldn't bother me. Like of course I didn't help their child as much as their teacher.
Also, we loved donuts

You could also add a fruit or veggie tray for people who can't eat them. We had several staff members who were gluten-free/vegan/on diets and no one ever complained that someone brought donuts they couldn't eat.