Responses
I think it's just because his dad thought it was cute how he would try to get him to tell the recipie, so he never did... but then he died and natsuki never knew and it kinda didn't matter anymore
Now that Chika knows it, I think it's a combination of him also thinking it's cute and he knows it will bring him good memories of his dad if he does the same thing
It doesn't have a deep reason, he just thoughtbit was cute/funny specially with Natsuki's reaction.
Now is a way to keep his memory alive.
I still dont get why they wont tell him the recipe?
I thought maybe they put something terasima hates like brocoli or smthn but he ended up not noticing and even liking it... whut why??? Im confused