Soak the dried navy beans overnight in a large bowl of water. Alternatively, use the quick soak method: boil the beans in water for a few minutes, then let them sit for an hour.
After soaking, drain and rinse the beans thoroughly to remove any debris or impurities.
Place the soaked beans in the slow cooker. Add the chopped onion, minced garlic, brown sugar, maple syrup, molasses, Dijon mustard, smoked paprika, black pepper, and salt.
Stir in the ketchup and water (or vegetable broth) until all the ingredients are well combined. Add crumbled bacon if desired.
Cover the slow cooker and cook on low for 6-8 hours or on high for 3-4 hours. Stir occasionally, adding more liquid if needed to keep the beans moist.
Check the beans for tenderness after cooking. If they aren’t done, continue cooking for another 30 minutes to 1 hour.
Serve the baked beans warm, garnished with additional bacon bits or fresh parsley if desired. Enjoy!