Place all ingredients in a 5 – 6 quart slow cooker and stir to combine.
3 Cups Dry Pinto Beans, 1 Medium Yellow Onion, 1 Medium Jalapeño Pepper, 3 Cloves Garlic, 5 Teaspoons Kosher Salt, 1 Teaspoon Freshly Ground Black Pepper, ½ Teaspoon Ground Cumin, 9 Cups Water
Cover and cook on HIGH for 8 hours, adding more water if needed to keep the beans in the cooking liquid as they cook.
Once the beans have cooked and are tender, strain them, reserving the cooking liquid.
Mash the beans with a potato masher (or the paddle attachment of a stand mixer), adding a little bit of the reserved cooking liquid as needed to get the desired consistency.