Add all ingredients to your cooking vessel and stir.
If using an Instant Pot, pressure cook on high for 35 minutes, then manual release.
If using a slow cooker, set to high for 8-9 hours.
When beans are finished cooking, use a ladle to reserve about 2 cups of the cooking liquid. Set aside.
Mash the beans and remaining liquid with an immersion blender or potato masher (a hand mixer will work, too). Add in reserved liquid as needed to reach desired consistency.
The beans will stiffen as they cool, so you may want to keep the reserved liquid to add more in later on.