Attitude Adjustment

My daughter is a very smart little lady. She speaks very precisely, enunciating every word and you can tell she really thinks before speaks... something I'm still working on! She is respectful and kind to others -- except when she bullies her younger friend, Josie. Poor girl, haha. So here's the problem... lately, more than ever, her mouth is getting her in trouble. Just towards me, really. I don't even notice it much with Jon. JUST ME! I try not to freak out because I know she feeds off of that. I already see ME in her frustration... YIKES! I've rubbed off on my daughter the one way I didn't want! I have little patience and I can see that in her as well. So in order to fix her, I'm trying to fix me. I'm glad that I can admit where I'm going wrong and I'm able to act quickly because if she were 16 and I was trying to fix her behavior, I'd have a big problem on my hands!

Here is what I do when her mouth gets out of hand - and by 'out of hand' I mean yelling 'NO!' at me or 'I DON'T WANT TO!' ...or really just throwing a screaming/kicking fit.

1. I warn her.
2. If she does it again, she gets put in a timeout. Timeout is in her room, sitting on her bed for 3 minutes or more.
3. Then she comes out and apologizes. I explain what she did wrong and forgive her for acting that way. We kiss and hug and it never gets brought up again.

Pretty textbook to me. Except when she does it again... and again. This does not happen everyday, thankfully. Just sporadically when she decides to push my buttons, usually resulting from lack of sleep on her behalf. I also know that food can trigger behaviors. The healthier the BETTER! Rather than processed junk, I've always tried to feed her 'natural' foods. Anyway, I'm consistent with her and the way she is disciplined. Jon is also on the same page, but like I said, it rarely happens with him.

Do I keep being consistent and hope she stops the behavior with age? Or should I try something new? Taking things away from her that really matter is my next step. I've done it before and it works. Should I bring it back and stay consistent with that?

Parents, I need your advice! HELP!