Agnieszka Mruk, accounts assistant for First bus group in Chelmsford, won first prize in the company's pumpkin competition.
The 22-year-old said: "This was my first pumpkin, so I didn't really expect to win the competition – I am pleased and very surprised.
"The lantern took me the whole evening to make, I cut my fingers and destroyed a knife in the process – but it was worthwhile."
Agnieszka and her colleagues each paid £1 to enter the competition as well as making a donation to wear casual clothes for the day.
James Chesters, marketing assistant, arranged the day to raise money for his Macmillan Peru hiking challenge in June 2009, when he will be tackling the famous Inca Trail.