Dishes is a layout that stacks extra windows underneath the master windows.

You can use this module with the following in your ~/.xmonad/xmonad.hs:

 import XMonad.Layout.Dishes

Then edit your layoutHook by adding the Dishes layout:

 myLayout = Dishes 2 (1/6) ||| Full ||| etc..
 main = xmonad defaultConfig { layoutHook = myLayout }

For more detailed instructions on editing the layoutHook see:

XMonad.Doc.Extending