Add all the ingredients, Except Cornstarch, to the instant pot and stir.
Turn the instant pot on to the pressure cook setting, high pressure for 35 minutes. Ensure the vent is sealed.
Once the instant pot is done, allow the instant pot to sit for 5 minutes before releasing the steam with the quick release method.
When the valve drops, open the lid and turn the instant pot setting to saute for 5 minutes
Remove about ¼ cup of the liquid from the beans and pour into a small bowl.
Add the cornstarch and mix until everything is dissolved
Pour the cornstarch slurry into the beans and stir.
Allow the sauce to thicken to the desired consistency. For a thicker sauce, you may mash some of the beans or add an extra tablespoon of cornstarch.