1pound navy or pea beans, soaked in water overnight
1/4cup vegetable oil
1cup chopped onions
1/2cup pure maple syrup
1/2cup canned tomato puree or crushed tomatoes
1tablespoon Dijon mustard
1/2cup brown sugar
Drain beans and combine with 4 quarts fresh hot water in large pot. Bring to boil and reduce heat. Simmer, partially covered, just until tender, 1 1/2 to 2 hours. Drain, reserving cooking water. Place beans in a large, shallow baking dish.
While the beans cook, heat oil in large skillet. Sauté onions until tender. Remove from heat.
Preheat oven to 325F.
Whisk together 1 cup of reserved cooking water, maple syrup, tomato purée, molasses, mustard, brown sugar and salt in a medium bowl.
Add sautéed onion and syrup mixture to beans; stir well. Cover dish tightly. Bake 2 1/2 to 3 1/2 hours, until beans are tender. Check periodically to make sure they have enough liquid, adding more reserved cooking water if necessary.