"The Restaurant at the End of the Universe" by Douglas Adams
"'Good evening,' it lowed and sat back heavily on its haunches, 'I am the main Dish of the Day. May I interest you in parts of my body?' It harrumphed and gurgled a bit, wriggled its hind quarters into a more comfortable position and gazed peacefully at them.
"Its gaze was met by looks of startled bewilderment from Arthur and Trillian, a resigned shrug from Ford Prefect and naked hunger from Zaphod Beeblebrox.
"'Something off the shoulder perhaps?' suggested the animal. 'Braised in a white wine sauce?'
"'Er, your shoulder?' said Arthur in a horrified whisper.
"'But naturally my shoulder, sir,' mooed the animal contentedly, 'nobody else's is mine to offer.'
"Zaphod leapt to his feet and started prodding and feeling the animal's shoulder appreciatively.
"'Or the rump is very good,' murmured the animal. 'I've been exercising it and eating plenty of grain, so there's a lot of good meat there.' It gave a mellow grunt, gurgled again and started to chew the cud. It swallowed the cud again.
"'Or a casserole of me perhaps?' it added."
"The Restaurant at the End of the Universe" was first published in 1980. It is the second book in Douglas Adams' "Hitchhiker" series, and as such is the the sequel to "The Hitchhiker's Guide to the Galaxy."
I read "The Hitchhiker's Guide to the Galaxy" a couple of years ago, so my memory of that one was pretty fuzzy. Fortunately the beginning of this book recaps much of what went before, so it can be read as a stand-alone novel. The plot revolves around Zaphod's quest to find the true ruler of the Universe, and also (of course) the near-disasters encountered along the way.
It's not, in my opinion, as funny as the first book, but there are some hilarious bits towards the end. It doesn't really pick up speed until they reach the restaurant for which the book is named, but after that point it's just as good as "Hitchhiker's". If you loved the first novel, then you'll also like this one. Even if you haven't read the first novel, and are instead the kind of person who appreciates Monty Python, you'll like this one a lot.