Soak the beans in 1.5% salted water for 6-8 hours, ideally. (Or skip this step and just rinse the beans and increase cooking time substantially.) Drain the beans, rinse quickly.
To the pressure cooker, add the one pound of dried beans. Add 2 quarts water.
Peel and cut the white onion in quarters. To spice sacks, or cheesecloth tied with twine, add two quarters of the onion, 2 tbsp oregano (Mexican, epazote, or Italian), and 3 cloves of garlic. Set the for high pressure for 5-8 minutes (Mayocoba), or 4-6 minutes (Pinto), or 4-6 minutes (Black).
1 lb dried beans, 2 tbsp oregano, 1 medium white onion, 6 cloves garlic
Allow to release pressure for 25 minutes naturally, and then release the rest of the way. Taste for doneness – they need to be creamy and soft, but not overcooked. If they are not done, turn to sauté and boil until done.
While the beans cook, mince the rest of the onion, the jalapeno, and get 1 tbsp of the chipotle in adobo sauce (including one pepper). Mince the garlic. You can combine all of this into a storage container and put in the fridge while the beans cook.
1 medium white onion, 1 small jalapeno, 1 tbsp chipotle in adobo
When beans are done, drain the beans, reserve the bean-cooking liquid and discard the spice bags.
In a large skillet or Dutch oven over medium-high, heat the 6 tbsp oil until shimmering. Add the onions, peppers, and garlic and cook, stirring occasionally, until onions are translucent and lightly golden, about 5 minutes.
6 tbsp vegetable oil
Stir in beans and cook for a few minutes, lowering the heat some. Add ¼ cup of reserved bean-cooking liquid to start. Using bean masher, potato masher, or back of a wooden spoon, smash the beans to form a chunky purée; alternatively, use a stick blender to quickly make a smoother purée. Add more bean cooking liquid if needed, to make it just wet enough to cook down. Reduce heat to medium and cook, stirring, until desired consistency is reached. Season with salt and pepper and serve.