Eating biscuits

Read books about food wastage. Talk to him about good habits. Maybe also ask for the reason why he dont want eat the middle part? Maybe he just wanna do the “sharing is caring” with family. But u know the reason and it’s not a good habit, then never give a second pc even if throw tantrums. Once you give in, baby wins and he knows that whenever he cry / throw tantrums he will win. First few tantrums usually very bad, but once they know it’s useless, they will stop.