In the pressure cooker, with the top off, over medium heat soften onions with the sage, salt and pepper.
When the onions are soft, scoot onions aside and tumble in enough squash cubes to cover the base of the pressure cooker, let brown for for about 10 Minutes stirring infrequently
Add the rest of the squash along with the ginger, nutmeg, and stock.
Close and lock the lid of the pressure cooker. Cook for 15 Minutes at High Pressure.
When time is up, open the cooker by releasing the pressure.
Fish out the woody sage stem and discard.
With a stick immersion blender purée the contents of the pressure cooker and serve!