We had to "google" this as we haven't seen on before.
From doing a search on "big fat round orange spider", we came to the conclusion that is is a 'type' of Orb Weaver Spider - there are many types. On deeper research, I'm pretty sure it's called a Nocturnal Orb...which would make sense considering she was building this quite late at night.
Although it must hurt pretty bad to get bit by one of these (they are shy to biting though), their bites are not harmful to humans...whew!
They can make webs up to a Meter across, which can actually score a small bat or bird....WOW!
They take down, and often eat, their webs at the end of the night, making a new one each day.
There ya' go, your daily spider lesson all in one places, LOL.