SOLVED. Read in the early 2010's: YA Fantasy? definitely fiction. About fallen angels fighting against heavens angels. Spoiler.

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I remember the angel being able to teleport & at one point he goes to Paris to get croissants when he's trying to impress her.
Also there's a character Lucifer who shows up on her porch and the angel gets mad the girl talked to him without him there.
For some reason I want to say Santa had come through the portal and was now living on earth??? He might have also been a bakery owner??
The girl was alone cause her parents & sister went through the portal so she made her own family on earth. Then the angel comes through the portal and decides to help her. OR he knew that the portal was actually to heaven and her parents died. I think that was the plot twist at the end.

Sorry it's not a lot to go on but thanks for trying!! (:

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Also, I forgot to say this was a series. So like the whole series is about fallen angels & heavens angels fighting, I'm pretty sure they were fighting for Earth.
But the first book is about the girl trying to find her parents.

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I found this in another group. It's called the watcher chronicles.