From Longman Dictionary of Contemporary Englishbe a piece of cakebe a piece of cakespokenEASY to be very easy ‘How do you do that?’ ‘It’s a piece of cake! Watch!’ → cake
Examples from the Corpus
be a piece of cake• The one he was allocated, Parky, a homely, Hoomey-sized bay, was a piece of cake compared with Bones.• Creating graphs is a piece of cake on the computer.• Should be a piece of cake.• Normally, walking along tarmac is a piece of cake after the rocky excursion along a ridge.• That was a piece of cake compared to finding a square mile without an ad.• My bone marrow was harvested a couple of weeks ago and the whole thing was a piece of cake.• But there is no use pretending the Saturn-Pluto effect will be a piece of cake.• Getting tickets to the game will be a piece of cake.be a piece of cakebe a piece of cakeinformalEASY to be very easy to do Landing this type of aircraft is a piece of cake for an experienced pilot. → pieceExamples from the Corpus
be a piece of cake• The one he was allocated, Parky, a homely, Hoomey-sized bay, was a piece of cake compared with Bones.• Should be a piece of cake.• Normally, walking along tarmac is a piece of cake after the rocky excursion along a ridge.• That was a piece of cake compared to finding a square mile without an ad.• My bone marrow was harvested a couple of weeks ago and the whole thing was a piece of cake.• Glacier walking is a piece of cake; well this bit was, with rolling hills of dazzling serenity.• But there is no use pretending the Saturn-Pluto effect will be a piece of cake. 