I finally bought one of these thermoses (its actually a Stanley, and a pretty good price): https://www.walmart.com/ip/Stanley-Adve ... r/44578871
You just put some hot water in it while you're heating up the soup or pasta or whatever you're putting in it for lunch. Dump out the water and load with the hot food. It holds about 2 cups and keeps it hot for hours! It works for cold too, but we haven't tried that yet. Just wanted to share in case someone else could use one!