Turn the pressure cooker on and set the "sear/saute" function and a "medium" temperature.
Add half the butter and onions to the bottom of the cooking pot. Saute until the onions are translucent.
Add the remaining ingredients to the pot and mix to incorporate. You can save the salt, pepper, and red pepper flakes until the end if you wish to season to taste.
Add the pressure cooker lid and set the venting knob to seal.
Cook the cabbage on high pressure for 6 minutes.
Set the pressure cooker lid to "vent" to quickly release the pressure.
Add salt, pepper, and red pepper flakes to taste.
Video
Notes
I was able to double the recipe for larger cabbage heads in my 8qt pot. Simply stir as you go to incorporate the ingredients as they are added.