It does seem like the exact challenge that would motivate him into a free cupcake.

[and jyn is all about that four letter word. f-r-e-e. even though they can afford to buy his cupcakes, which is a very weird thought.]

[cassian has had no real family of his own, but it doesn't mean he can't read into dynamics and figure out how to use them.]

They are both good cooks who seem to thrive off one-upping each other.