Soak the dried beans in several inches of water at room temperature for 8 hours or overnight. Drain, but reserve 3-4 cups of the soaking liquid.

Preheat oven to 250°F. In a large oven-safe pot or Dutch oven, cook the bacon over medium heat until about half done (not crisp), just a few minutes.

Add the onion and jalapeños right into the pot with the bacon and sauté together until the onion softens, about 5 minutes.

Stir in the tomato paste and sauté for about a minute to caramelize it slightly.

Add the molasses and brown sugar, stirring until combined.

Add the beans, the reserved 3-4 cups of soaking liquid, and about 4 cups of vegetable, chicken, or beef broth. The liquid should sit a couple of inches above the beans — they'll absorb a lot as they bake, and plenty will evaporate even with the lid on.

Stir in the cayenne, black pepper, and salt.

Cover and bake, checking doneness around the 5-hour mark. If the beans are already thick and tender, they're done. If they're still thin, remove the lid for the last 30 minutes to an hour and let them reduce — though in practice they usually come out thicker than you'd expect even without this step, so don't be shy with the broth going in.