Homemade "Refried" Beans

1 onion, peeled and cut into quarters
3 cups dry pinto beans, rinsed
1 1/2 t jalapeno, finely chopped (pickled or fresh - remove the seeds and veins if fresh)
2 tablespoons minced garlic
5 teaspoons salt
1 3/4 teaspoons fresh ground black pepper
1/4 teaspoon cumin seed
9 cups water

Place the onion, beans, jalapeno, garlic, salt, pepper, and cumin into a slow cooker. Pour in the water and stir to combine. Cook on High for 8 hours, adding more water as needed. Once the beans have cooked, strain them, and reserve the liquid. Put the beans in a mixer and mix until mashed to desired consistency. Add some liquid if needed.