Also
Oh My Ghostess: he's a star chef and she's a clumsy assistant. He eventually falls heads over heels for her, though he keeps reminding her about how he's the "great Sun Woo" and she should be honoured -- of course his insecurity is so obvious it's endearing rather than annoying, haha
When A Man's in Love: as ever beware of this drama, since it displeased many people. In any case, they meet while he's a loan shark and she's a highschooler whose family he's bullying for money. It's love at first sight for him, so he gives her money for her studies, cleans up his act and becomes the wealthy head of a large conglomerate or something. Several years after they meet again, and she's still struggling, so he hires her *supposedly* for her to repay her debt to him, but of course it's because he loves her. The reason why many people disliked this drama is because the heroine is rather cold.
Second Time Twenty Years Old (currently airing): not boss - employee, but rather teacher - student, so there's a similar dynamic where he's at the top of the ladder and she's way at the bottom. He knew her when he was an outcast boy and she was a popular girl in highschool that was kind to him, only they meet again when she starts attending college at 38 or something (everyone gives her a hard time about it), and he's a respected professor.
Technically Que Sera Sera has a boss falling for his employee, but if it's a straightforward and sweet romance you're looking for, then stay away from this drama (though I loved it). Angst and love tangles alert!
It's short and extra light, but in EXO Next Door, an idol and the girl that's hired to clean their house end up together.
And I second Rich Man, Poor Woman
