The organisers said Julie and Julia: 365 Days, 524 Recipes, 1 Tiny Apartment Kitchen, by 32-year-old Texan secretary Julie Powell, beat 88 other "blooks" from 12 countries.
The book scooped the $A2,800 prize awarded by Lulu.com, which claims to be the world's fastest-growing provider of print-on-demand books.
Ms Powell's musings on attempting to cook all 524 recipes in Julia Child's 1961 cookbook, Mastering the Art of French Cooking, in the confines of her tiny New York apartment kitchen attracted a cult following on the internet.
Her blog-based book has sold more than 100,000 copies.
"I had no idea what a blog was a week before I began," Ms Powell told British daily The Guardian.
"The medium really liberated me and motivated me to do the work and not obsess over the details. The community aspect of blogging and the interaction with others kept me honest, kept me writing and kept me from sinking into my habitual self-loathing."
Weblogs are an increasingly prominent medium, with a new blog being launched every second.
Blooker Prize judge Paul Jones explained "A great blook isn't a website shovelled onto paper. Julie and Julia successfully makes the transition and grows as it goes, having learned from the blog readers."
Weblogs were recently placed under the spotlight when an anonymous Iraqi university graduate, who uses the pen name Riverbend, was nominated as a contender for a major literary award.
Her blog-based account of the war in Iraq and its deadly impact on ordinary Iraqi people, Baghdad Burning, was longlisted for the $A73,000 Samuel Johnson prize, the world's richest for a piece of non-fiction.