Soak the Beans: Rinse 1 pound of dried navy beans and soak them in water overnight (at least 8 hours).
Preheat the Oven: Preheat your oven to 300°F (150°C).
Combine Ingredients: In a large oven-safe pot, mix soaked beans, 1/2 cup molasses, 1/3 cup brown sugar, 2 tbsp mustard, 1/2 tsp salt, 1/4 tsp black pepper, and 4 cups water. Optionally, add chopped onion and bacon or salt pork.
Bake: Cover the pot and bake for 6-8 hours until beans are tender and the sauce thickens, adding water if needed.
Check Doneness: Test beans for tenderness after 6 hours, continuing to cook until desired consistency.
Adjust Seasoning: Taste and adjust salt, sugar, or mustard to your preference.
Serve: Let beans cool slightly before serving as a side or main dish with cornbread, coleslaw, or grilled meats.