Dice up the onion into ¼" dice. Rinse the beans and remove any stones, debris or any discolored beans.
Add the water, beans, bay leaf, dry mustard, cumin, salt, and diced onion to the inner pot. Stir. Put the pressure lid on and turn the valve to seal. Select high pressure and set the time for 30 minutes. Allow the pot to naturally release the pressure for 15 minutes. If any pressure is left, manually release it.
Remove the beans and liquid from the inner pot and place into a deep bowl. Use an immersion blender to blend to the consistency you like. Do not worry if they are runny, the next step will fix that.
Turn the Ninja Foodi on high sear/sauté and add bacon fat or lard. When melted and hot, add in the bean mixture and sauté on high until it thickens to your desired consistency.