I learned a new trick from the USDA: when keeping hot stuff hot, fill the thermos with boiling water for a few minutes before adding the hot food. It works like a charm according to the kid, who reported that her rice and beans were nice and hot. Today I ended up with: ice pack on bottom, grapes, crackers in plastic box as a barrier with the rice and beans hanging out on top. Water and kid-approved seaweed snack: Done!
Don’t waste that nice hot water you left until it was the perfect temperature to brew a nice cup of tea. See? Now everyone’s happy.