This is a normal development at this age, influences by friends, coming into her own tatses etc. You're right to be concerned. You have to re- set the rules now, so she naturally resets her own respect level before this gets worse.
At her age, she needs to be re-educated in your role and what you will not allow. Have a serious talk (I'm sure you have, but come to this one prepared with clear consequences) to send the message that if she is a good and intelligent girl (which she is), who wants to be respected and admired, she knows it is not nice to treat ANYONE this way. Would she smart off to her teacher? Would she smart off to her friends? (maybe, I'm sure they're all practicing up on their girly sassiness, but that doesn't mean she can do it to you, let her know) Then SURELY, she should not speak this way to the most important person in her life-you. I know you've probably told her all that, SO,
Explain to her why complaining about her food etc is sending you the message that she must be very spoiled and entitled, and perhaps she needs to start earning and/or making her own food if she thinks it's OK to insult what she's being given for free. Don't just say it, stop giving her yummy meals and give her un-yummy ones until she learns to be nice and earn the yummy pasta with good manners and respect. IN addition to this "long term consequence" which is sort of broad on it's own for a 7 year old, also do something immediate and firm when she does it. Every time.
No grudges after consequences are doled out, go back to your nice positive day, and keep your higher ground, but react the same way whenever she does it.
I saw a great episode of the World's Strictest Parents when they took some spoiled bratty teens in and the first night there, the guest rooms had just a bare mattress and no furniture. The teen boy did something disrespectful to the host when he first arrived so he no longer had the free gift of the mattress and slept in a sleeping bag. Through the week they had to perform community service for poor people and do chores around the farm and learn respect and gradually earned back respect for themselves and compliments and all the furnishings for comfy rooms, and it REALLY changed them-I couldn't believe it would work so well so fast. At first they were just used to having all the comforts of home without earning anything.
I would start to find consequences in relation to what she's complaining about and broaden her perspective (not instead of something immediate and firm at this age, but in addition to). Tell her in advance exactly what you are doing and what will happen specifically if she speaks unkindly to you again, and follow through immediately.
CONSISTENTLY so she never gets away with the little jabs. they WILL get worse if you don't, and they WILL go away if you do.
Instead of not going for ice cream when it happens, maybe pre-emptively tell her she's not going to go get ice cream ANYMORE until you see she has not smarted off to you for as long as you need to be convinced in addition to the immediate discipline she'll get when she says rude things to you. Hates your house? Instead of taking random things away when it happens, maybe remove her adorable girly decor in her room until she earns the princess curtains (or whatever she has in her cute room) back by being respectful to you. She will be proud of herself when she earns them back. Explain that everything you do for her is because you are respectful and kind and love her, but you don't have to do these things, if she doesn't deserve it. She has to treat you nicely in return for how nice you are to her.
Also, set up some special days with you and her together where she sees that other people do not have everything she has. Help a family out who live in a bad home so she sees how nice hers is. Watch some videos of poverty stricken places. My four year old was really affected by the earthquake in Haiti on the news when I explained to her that the people didn't have houses to live in like us. Find something nice to do to volunteer together somewhere. The bonding will help as well as the lesson for her. She sounds like she is getting a little spoiled (normal for all of our well-provided for kids) and you are doing her character a great service to get this fixed now!