Place all ingredients except green onions into the inner liner of your Instant Pot or Pressure cooker.
Cook on high pressure for 45 mins (can also use Bean cycle). Allow it to release pressure for 10 minutes, and then slowly release all remaining pressure. If it foams, stop and start the pressure release, or just wait a little longer for more pressure to release naturally.
Using an immersion blender, roughly purée some of the soup to thicken it while leaving other beans intact.
Garnish with green onions and serve.
For Slow Cooker
Place all ingredients into a slow cooker and cook for 8-10 hours on high, or until the beans are soft. If you want to speed up cooking time, use beans that have been soaked the night before, or soak beans in hot water for 1 hour prior to cooking.
Using an immersion blender, roughly purée some of the soup to thicken it while leaving other beans intact.
Garnish with green onions and serve.
If you have more time, brown the bacon and diced onion separately while the soup cooks and add at the end for a burst of flavor!
Leave the bacon out entirely for a Vegan version.
You can use red beans for this soup if you prefer.
You can also pour all the ingredients into your slow cooker and make a great slow cooker black bean soup in this fashion.