Soak the beans for 1 hour. After 1 hour, drain the beans and transfer to the pressure cooker. Cover with 8 cups of water. Make sure you don't go over the allowed water level for your pressure cooker. Add 1/2 the onion, 6 cloves garlic, jalapeño, 2 bay leaves and 2 - 3 tablespoons of oil. The oil will prevent the beans from foaming up, which is better for pressure cooker method.
Secure and lock the lid of a 6 quart pressure cooker. Cook on high until the security valve seals and pressure cooker begins to hiss. It may take 20 minutes or more for it to come up to pressure and lock. Reduce the temperature in between medium/low. If you have an electric stove, set it at number 4. Set timer for 30 minutes. The time depends on the size of pressure cooker sometimes. In my experience anyway. Carefully remove from heat and wait for safety valve to release. Agai, this may take 20 minutes.
Once it releases, unlock and open lid. Check for tenderness of beans. If beans are still a little tough, cook uncovered for 10-15 minutes at medium heat. Season to taste with salt. Remove the bay leaves. If preparing fried beans, using a slotted spoon, add all of the beans, including onion, garlic and serrano to the blender. Ladle in just enough bean broth to fill blender. Cover tightly and blend until smooth. Set aside. If you prefer, you can mash with the potato masher once in the skillet.
For Fried Beans: In a large, deep skillet, preheat 3 tablespoons of avocado oil to medium heat. Once hot add 1 cup diced onions and 1 minced serrano pepper. Sauté for 6 to 8 minutes. Carefully pour in the beans from the blender. Continue cooking for 7 to 8 minutes at a light simmer. If you want a thicker bean, cook a little longer. If you like a thinner bean, add some chicken broth or water.