To maximise a window/application minimised in the Dock on OS X, follow these steps.

  1. Hold down the Command key (⌘) and press the Tab key (⇥) to bring up the Application Switcher. Press Tab to focus on the desired application.
  2. While still holding the Command key, press the down arrow (↓) to activate the Application Exposé view.
  3. With the Command key still held, use the left and right arrow keys (← →) to select a minimised window. Press the Enter/Return key (⏎) to maximise the selected window.

See the video below for a demonstration

Reverse navigating through the Application Switcher by holding down the Shift key (⇧) is supported.