How to fire a long term nanny?

Or nanny has been with us since our two year old was an infant, and she was amazing with him. But his little brother was born a few months ago, and everything changed. She’s just not a great fit for taking care of the two of them together. We’ve tried to address the performance issues as we see them, and are having a more direct conversation this week about what we’d like to see change. But we’re not optimistic about it.

We’ve also never had to fire anyone before, and we’re not sure how to actually go about it. We know we want her last (working) day to be the day we tell her we’re letting her go. We’re worried that once she knows she’s losing her job, she’ll be even less engaged than she already is, or worse, actively retaliate.

But we’re not sure when or how to actually deliver the message. On the one hand, we’d like to give her time to say goodbye to the kids (and especially our oldest). On the other, we’re worried about her getting angry (we’ve never seen her anger in person, but have been on the receiving end of some of her lengthy rage texts ) and don’t want the kids to get caught up in it. We are planning to provide two weeks pay to hopefully soften the blow, but not sure how much that will help.

Has anyone been in a similar position? There’s probably no good way to do this…but is there any way to make it less bad?