Indonesian/Malaysian Cookbook with Authentic Recipes?
Rasamalaysia.com!!! Great blog; I've been to Malaysia a couple of times and can vouch that every recipe I've tried has been pretty much spot on, though there are a few ingredients I can't get in the states. She's a Nonya, originally from Penang, I believe, so she specializes in Perenakan food, but has plenty of great Malay, "straits Chinese", Thai, Indonesian...actually, recipes from all over Asia. And her pics are food porn at its finest.
You might take a look at Cradle of Flavor: Home Cooking from the Spice Islands of Indonesia, Malaysia, and Singapore, by James Oseland. Oseland spent some years in the area learning the cooking, and has plenty of information in the book about the foodways and ingredients.
This one was a Cookbook of the Month on Chowhound a couple of years ago, so there are reports of people's experiences with the recipes that'll give some idea of the contents. The main thread for that is here: http://chowhound.chow.com/topics/616583
I have Indonesian Regional Cooking by Sri Owen. I've only had my *own* Indonesian cooking, so I cannot attest how authentic this is, but, in the foreword, the author states that her desire to write this book came from the feeling that her land was losing its food traditions. She had a desire to record what she considered to be traditional and classic recipes from each region, and I've always been assured by that.
She does make note of when substitute ingredients are advisable, in order to accommodate a wide range of markets in different countries, or very difficult to replicate faithfully. The book also serves up a bit of history, which I like, and has a decent glossary in the back to ease translation. The book, however, is a bit meat heavy. There are a decent number of vegetarian recipes, but this book is more of use if you at least eat fish and shellfish.
Hermes House (HH) a British publisher has a series regional cookbooks. I have their Singapore-Malaysia volume. There are often available at clearance prices in bookstores. They are heavily illustrated, and include a introduction to relevant ingredients. These volumes include a number vegetable dishes - which aren't necessarily vegetarian (in the Western sense).