Season the oxtails with the salt and pepper.
Heat the butter in the Instant pot over the normal saute setting.
Add oxtails and brown on all sides, about 3-5 minutes per side.
Add onions and garlic and saute for about 2 minutes.
Add the sake and cook another 30 seconds, using a wooden spoon to scrape all the browned bits from the bottom of the pot.
Add beef broth, broad bean paste and Chinese five spice.
Set the Instant Pot to pressure cook for 60 minutes on high. Let the pressure release naturally for 15 minutes, then use the quick release to release any remaining pressure.
Once the pressure has been released, remove the lid and bring back to a simmer on the saute setting (low).
Add the cream and simmer until reduced and slightly thickened, about 5-10 minutes. **If sauce is too thin, use a cornstarch slurry (see recipe note #2)
Serve over egg noodles, rice, potatoes, etc. (See post above for serving ideas)