Ok, I tried to do some of the layer mask type stuff, but I'll admit I didn't do as good a job doing the selection as some people can...
So, let's see...
My first step was selecting around the cake so that I could work with a few different adjustment layers.
I selected the inverse to work with the white background, and used a selective colour layer to remove the black from the neutrals.
I selected the cake again using the inverse selection, and created a new selective colour layer and increased the amount of black, and then darkened the magenta and yellow, and finally removed some of the black from the neutrals to make the plate whiter.
I wanted the cherry and leaf to stand out more, so I increased the saturation of the red and green using a Hue/Saturation Layer.
I used an unsharp mask on the cake layer.
Then added some text using the colour dropper to pick out a red from the cherry on top.
I think that's everything. Oh, and did a square crop.