How to get Cascading Folder Browser in Dock or Menu?
You can use the Stacks feature on the Dock to accomplish what you're asking.

You can drag and drop the Macintosh HD (or any other folder) onto the right side of the Dock, to the right of the separator line, to create a Dock item. Then right-click it, to bring up its context menu, and select List under View content as. This will give you a cascading menu of the drive.

For more information on Stacks, have a look at: Mac Basics: Stacks are your shortcut in the Dock