Pick over the dried pinto beans to remove stones or damaged beans. Rinse them well, then soak them overnight in plenty of water; drain and rinse before cooking.

For a quick soak, boil the beans for 2 minutes, remove the pot from the heat, cover, and let them stand for 1 hour. Drain and rinse before continuing.

In a heavy pot, cook the diced bacon over medium heat until lightly crisp. Remove a little bacon for garnish if desired; if omitting bacon, heat 1 tablespoon of bacon fat or olive oil instead.

Add the diced onion and cook for 5–7 minutes, until softened. Add the garlic and jalapeño, if using, and cook for about 1 minute.

Stir in the cumin, chili powder, oregano, and black pepper. Cook for 30 seconds to bloom the spices without letting them scorch.

Add the soaked beans, bay leaves, and 8 cups of water or unsalted stock. The liquid should cover the beans by about 1–2 inches.

Bring the pot to a boil, then reduce it to a gentle simmer. Partially cover and cook for 1 1/2–2 1/2 hours after soaking, stirring occasionally and adding hot water as needed; unsoaked beans may take 2–3 1/2 hours.

Add the kosher salt during cooking or once the beans begin to soften, then adjust to taste. When the beans are creamy and tender, remove the bay leaves, stir in lime juice or cider vinegar if using, and mash about 1 cup against the side of the pot before stirring it back in.