Step 1

In a medium bowl, cover beans with cold water by several inches and stir in 1 tablespoon (15g) salt. Let beans soak at least 12 hours and up to 1 day. Drain and rinse.

Step 2

Combine beans with aromatic vegetables and herbs (if using) and bay leaf in a large pot and cover with water by several inches. Add a generous pinch of salt. Bring to a boil, reduce to a simmer, and cook, topping up with water as necessary, until beans are fully tender, about 45 minutes. Using tongs, discard vegetables and aromatics.

Step 3

Meanwhile, pour molasses into a 2-cup liquid measuring cup. Add mustard, a very generous dose of freshly ground black pepper (let it rain!), and a pinch of salt.

Step 4

Drain beans, reserving cooking liquid. Add enough bean-cooking liquid to molasses mixture to bring the volume up to 2 cups (475ml) and stir until molasses is completely dissolved. Reserve remaining bean-cooking liquid.

Step 5

Preheat oven to 325°F (163°C). In a Dutch oven, cook pork over medium-high heat, stirring occasionally, until fat is rendered and pork is beginning to lightly brown, about 4 minutes. Add onion and cook, stirring, until onion is very tender and just beginning to turn golden, about 6 minutes. Add beans to pot.

Step 6

Add bean water/molasses mixture and stir well to combine. Add enough reserved bean-cooking water to just barely cover beans, then stir once more, leveling out beans so that none are sticking up above the liquid level. Bring to a simmer.

Step 7

Transfer beans to oven and bake, uncovered, until beans are extremely tender but still mostly whole, with only a small fraction beginning to burst, about 4 hours. Check beans once or twice per hour during baking, adding remaining bean-cooking liquid (switching eventually to boiling water if you run out) as needed to prevent the beans on the surface from drying out. Stir beans twice during the baking process to submerge the top ones, leveling them out each time; over time, a dark, browned crust will form on the surface of the beans (this is good). The goal throughout is to keep the liquid level just high enough that the upper beans don't desiccate, but not so high that the surface doesn't brown. Stop adding liquid during the last hour of baking unless the level becomes perilously low.

Step 8

Remove beans from oven and stir them very well. The sauce should form into a thickened, starchy glaze. If it's too dry, add boiling water sparingly until a glaze is achieved; if it's too wet, simmer briefly on the stovetop until reduced to desired consistency. Adjust seasoning with salt and pepper. If beans are too sweet for your taste, a small splash of cider vinegar can help balance the flavor (though I never thought my beans needed it).

Step 9

Keep warm until ready to serve. Beans can be refrigerated for up to 1 week. Reheat in a saucepan, adding water gradually as needed to loosen them back up.