When hot, add the onion and cook until the onion is translucent, approximately 5 minutes.
Add the cumin, garlic powder, cayenne, and salt. Stir to combine and cook until fragrant, approximately 1 minute.
Add the beans and stock to the pot. Simmer over medium heat 15 minutes for the beans to soften and begin breaking down.
Mash the beans with a potato masher to your desired consistency. Add more stock or water to make it thinner and smoother. Serve warm.
Notes
For an ultra smooth bean, process the ingredients in the food processor or a blender. The cayenne does not make it spicy but adds to the flavor. For spicy beans, add more as desired to taste.