How long should I blanch baby peas? I have a recipe which calls for a cup of blanched baby peas.

Now, I know what blanching is. It concerns cooking the outer layer of green vegetables (James Peterson), but how long should I blanch baby peas? 

It seems that even a few seconds would cook them all the way through.
15-20 seconds seems to be all it needs for me, and then scoop them up and shock them in iced water to stop them cooking.