Add the navy beans to a large container and cover them with water by about 4 inches. Set aside overnight.
Preheat the oven to 325°.
Drain the beans, rinse them, and set them aside.
In a medium to large size cassoulet pot or Dutch oven, add in the bacon and cook over medium heat until crispy, about 6-8 minutes.
Set the crispy bacon lardons aside and then add in the onions. Turn the heat down to low and cook until well browned about 30-40 minutes. Stir occasionally.
Add in the garlic and peppers and cook for 6-8 minutes on low to medium heat. Stir occasionally.
Add in the remaining ingredients, rinsed beans, tomato puree, mustard, tomato paste, vinegar, molasses, brown sugar, hot sauce, beef stock, salt, and pepper, and mix until completely combined.
Cover with a lid and bake in the oven at 325° for 3 to 3 ½ hours or until the beans are tender and the mixture is thick. You may need to add ½ to 1 cup more of beef stock at the 90-minute cooking mark.
Garnish with additional crispy bacon and optional chopped parsley or sliced chives.
Chef Notes:Make-Ahead: You can make these up to 1 day ahead of time; simply reheat them before serving.How to Reheat: Add the desired amount to a small saucepot and heat over low heat until warmed. You can also heat in the microwave.How to Store: Cover and store for up to 7 days. Cover and freeze for up to 3 months. Thaw them in the refrigerator for 1 day before reheating.If you don’t have a Dutch oven pot, you can use your favorite oven-safe pot with a lid.To slow cook these, simply follow procedures 2-4 on the sauté function, and then once you add in all of the ingredients, slow cook on high heat for 6-7 hours.You can substitute the tomato puree for canned tomato sauce or blended or finely pureed fresh tomatoes.Swap out the dried beans for 6 15-ounce canned beans and reduce the baking time to 30 minutes. In addition, remove the beef stock completely.