DS is incredibly fussy and I’m after a healthy lunch box filler for him. We’re vegetarian so a slab of meat is not an option. I’m after a piece of cake or a slice or something he can have in one section of his bento box. Nut free is essential for his kindergarten, and low or no sugar would be great. I’m fine with fruit purées for flavour though I’m aware come would consider this sugar. 
Do you have any recipes like this your kids love? There are billions online but they always seem to crumble apart without the lovely sugar to glue them together. That or they taste horrible...