1 lb Great Northern beans, dried
16 oz Tomatoes; undrained and cut into eighths
3 MD Onion; chopped
1/2 lb Salt pork; cubed
1 c Sugar
1 tb Vinegar
1 ts Mustard, prepared
1 ts Salt
1/8 ts Pepper
Sort and wash beans; place in a large Dutch oven. Cover with water 2 inches above beans, and bring to a boil; cook for 2 minutes. Remove from heat; cover and let soak for 1 hour. Drain, reserving 1/2 cup liquid.
Add liquid and remaining ingredients to beans; spoon bean mixture into a 4-quart casserole. Cover and bake at 350 degrees for 4 to 4-1/2 hours or until tender, adding more water if necessary.