Cover beans in a large sauce pan with about 5 cups of water. Bring to a boil and cook 30 minutes. Drain the water off. Put ½ the bacon and onion in the bottom of the slow cooker. Mix all the other ingredients (except beans, bacon and onion) well. Mix beans and sauce together and pour into the slow cooker. Top with the remaining half of the bacon and onion. Cover beans with hot water (just). Cook, covered, on low 4 hours. Remove 1 cup of beans and mash them. Stir them back in to the beans. Cook, covered, another 3-4 hours on low. Make sure the beans are always just covered with water.

Follow slow cooker method except substitute a dutch oven for the slow cooker. Preheat oven to 300 degrees. Cook beans covered for about 7 hours. Check hourly and add water if necessary so beans are always just covered with liquid. 1 hour before serving remove 1 cup of beans, mash them and stir them back into the rest of the beans to thicken the sauce.

Cook navy beans in your pressure cooker according to your manufacturer's instructions. Mine is to add 6 cups of water for 2 cups of dry beans. Add 6 tablespoon oil to the water to reduce foaming. Cook on High for 7 minutes and allow slow, natural release. Follow the oven method above except you will only need to cook about 3 hours at 350 degrees. Check hourly if you need to add water.