Set the pot to the sauté setting and add the butter. Once melted, add the chopped onion and bay leaf. Sauté for about 5 minutes or until translucent.
If you’re using a ham bone, put it in the pot, then follow it with the rest of the ingredients.
Set to Pressure Cook (or use the manual setting, depending on your model instant pot), high pressure, and use the +/- button or dial to select 60 minutes (1 hour).
After cook time, leave pot undisturbed for 15 minutes to allow it to naturally release before manually releasing the remaining pressure.
When the pin in the lid drops down, carefully open the pot and test the beans for softness (test a few at random). Keep in mind that old beans will take longer to become soft, so if your beans are not soft enough, set the pot to cook an additional 15-30 minutes.
Discard bay leaf, taste and adjust salt if needed. Serve.