Drain the soaked beans in a colander and discard the soaking water. Transfer the beans to a medium saucepan, add 6 cups of fresh water, and bring to a boil over high heat.
Reduce the heat to a simmer and cook until the beans are tender, about 45 minutes to 1 hour. Set the beans aside to cool in the cooking liquid.
Position rack in center of the oven and preheat the oven to 300°F.
In a medium skillet over medium-high heat, saute the bacon until crisp and golden brown, about 5 to 6 minutes. Be careful of grease splatters.
Add the onion and cook, stirring, until soft, about 4 to 5 minutes.
Add the garlic and cook for 2 minutes.
Add the brown sugar and cook, stirring, until melted, about 2 to 3 minutes.
Add the ketchup, maple syrup, molasses, Worcestershire sauce, Dijon mustard, salt, and pepper and stir to combine well.
Set a colander over a mixing bowl in the sink and, using oven mitts or pot holders, drain the cooked beans away from you, reserving the cooking liquid in the bowl.
Transfer the beans to an ovenproof saucepan or casserole dish. Add the bacon-ketchup mixture and stir to combine well. Cover the saucepan with the lid or aluminum foil and, using oven mitts or pot holders, transfer to the oven.
Bake the beans, stirring occasionally, for 2 1/2 hours.
Using oven mitts or pot holders, remove the casserole, add 1/2 cup of the reserved cooking liquid, and stir. With oven mitts or pot holders, return the casserole to the oven and bake, uncovered, for 30 to 45 minutes more, stirring occasionally, until the sauce is thick and bubbly around the edges.
Using oven mitts or pot holders, remove the beans from the oven and serve.
YIELD: About 4 cups, serving 4 to 6