Really, honestly, don't do the passive aggressive pretending she doesn't exist shtick, it's so fucking horrible and damaging. My Mother was the fucking expert at this, she would then burst into my room after a couple of days/a week and demand to know why I was ignoring her
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I'm pretty sure a child would rather a lecture and defined punishments which are actually reasonable, these can be carried out, in the meantime the parent got the fuck over whatever crime they had committed (fair enough actual crime might be different).
I have to fight so hard not to be a passive aggressive loon who holds grudges and takes things ultra personally, it's so ingrained. A very accepting and persistently cheerful partner has gone a long way, I now only sulk for a few hours
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Have a rant at her, give her punishments (and carry them out) but don't do the whole go away/I can't look at you shit. She has marked her carpet and said something stupid in the heat of the moment, it's not that bad, you say she has been an angel until now, so she seriously deserves some understanding.