The cookbook idea is a star!
I love what you are doing for and with Sophie.
When I was in the school lunch game I got told by my daughter to let her take over. She was never a sandwich kid. Her favorite lunch was ramen soup (without the horrible salty/msg bomb flavor packet) put into a thermos with turkey lunch meat cut into cubes.. By the time lunch came around the noodles had turned into this weird congealed mass which she ate by cutting it into pieces in the thermos cup. Her friends were fascinated!
She brought a fruit cup every day and put shredded cheese on top. Peaches or pears with cheddar cheese--it's pretty good!
When she was in high school she didn't eat at school, except maybe a cup of yogurt. At 13 the idea of a boy watching her eat drove her crazy. She is 100& feminist now as an adult--so glad she got out of that phase.