Started by drawing two circles using the ellipse tool, selecting these in the Paths palette and filling with black(⇧F5). Then used the Warp tool to give a more realistic donut like shape.
This gives us a pretty convincing shape. Now to work on the the colour. Using a radial gradient overlay with the panel setting below.
Next adding drop shadow and an inner shadow. The drop shadow is simple enough. The inner shadow has the following values
The outer chocolate takes on a deeper color adding a touch of realism. In the satin option I reduced the opacity to soften the orange layer. Now for the toppings.
My final touch was adding a Bevel and Emboss to the toppings layer to give the more dimension.