How do I respond to a woman when she acts like a petulant little girl?

My girl is the youngest in her family and has always been spoiled and taken care of by daddy and his money. How do I mitigate these tendencies?

I've been making an effort to openly scold her when she whines and the like, and ruthlessly maintaining my frame. My mantra has been telling her that I will treat her like an adult when she acts accordingly. This morning she told me she would like to "punch (me) in (my) smug face," so I must be doing something right.

She shows no signs of improving. What can I do to actually instruct her to prevent future tantrums, not just mitigate them as they come?

Another thing: I have a full-time job, she takes care of the home life. Often she will ask (order) me to do something she could do, but doesn't want to do. It's always something relatively small so that I look crazy (or lazy) if I protest or refuse. Get response is always, "Oh, so you just don't help out around the house at all??" My thought is, well, yes. I work, you house. Is that unreasonable?

Help me be head of my house again.