A book about a woman who says she's God

[waitingonsunday]

I've been trying to remember the name of this book for years, and can never seem to Google the right selection of words to figure out what it is. I read it in '95 or so, and I want to say it was only a few years old at the time. I'm pretty sure it's told in first person, maybe even as some kind of journal the male main character is keeping. The MC befriends a mysterious woman who claims to be God. I think the title was one word, the mysterious woman's name. One of the MC's friends is outraged by the mysterious woman's claims and at one point is ready to drive a nail through her palm to somehow prove she isn't God. The woman is ready to go through with it, but I think the MC interrupts before it goes down. In the end (spoiler alert?), the guy's friend kills the woman and is very smug about the fact that she died just like any other person would, thereby proving she wasn't God. The MC drives out to the desert with his friend and the woman's corpse and forces his friend to dig a grave for the woman. Then the MC drives away, leaving his friend in the middle of nowhere with nothing but a shovel. The woman at some earlier point had given the MC a recipe for chocolate chip cookies, saying they'd change his life, and after her death, he sells the recipe to a big company and makes a fortune. No longer having to worry about a job, he sleeps in all day, and I remember some comment about the fact that he never gets less than 12 or 14 hours of sleep every night. At the end of the book, I think he says this slacker lifestyle is starting to bore him and he wants to do something productive.

Found!: Sati, by Christopher Pike. My thanks to tooimpurenangel for the speedy answer.