Called NeverSeconds, the blog was started by the Scottish pupil to raise money to help feed children in Africa.
The youngest ever winner, her blog caught the judges’ attention after documenting the daily school meals of children around the world.
In the process she has raised enough money to feed 10,000 children in Malawi.
Allan Jenkins, editor of OFM and awards chair, said: “With a higher number of public votes than ever before - up an amazing 60% since last year's record number - and with expert judges from Wales, Scotland, the Lake District, Midlands, the West Country and the South, never have the OFM Awards been so representative or relevant.
“Perhaps my favourite prize-winner is nine-year-old Scottish schoolgirl Martha Payne, whose NeverSeconds blog raised enough money to feed 10,000 Malawi children for a year and demonstrated there is more to food-blogging than moaning about Michelin stars or drooling over the latest hip burger joint.”
The winners of the 2012 Observer Food Monthly (OFM) Awards, in association with Cuisinart, were announced last night and included restaurateurs Terence Conran and Raymond Blanc, Hugh Fearnley-Whittingstall, and the chefs collective Young Turks.
The full list of winners:
Lifetime achievement
Terence Conran
Outstanding contribution
Raymond Blanc
Young chef of the year
Adam Smith, senior sous, Ritz Hotel Restaurant
Best newcomer
Young Turks, London
Best producer
Cultivate London
Best reader's recipe supported by Lurpak
Pulled pork roll by Rachael Wass
Best reader's cocktail
You Me @ Six by Peter Nielsen
Reader voted awards
Food personality supported by Cuisinart
Nigel Slater
Best cookbook supported by Harvey Jones
Hugh Fearnley Whittingstall - River Cottage Veg Every Day
Best food blog (in the UK) supported by Exclusive Hotels
Martha Payne, NeverSeconds
Best restaurant (over £20 per head) supported by Nyetimber
The Seahorse, Dartmouth
Best cheap eats (under £15 per head)
Tayyabs, London
Best Sunday lunch
The Parlour, Chorlton
Best ethical restaurant
Create, Leeds
Best place to drink
Zetter Townhouse, London
Best independent local retailer
Growing Communities, London