Soak beans overnight and then drain the liquid.
Add the beans to a large saucepan along with two cups of water and 1 tsp salt.
Bring to a boil and simmer, covered on low heat for 2 hours.
Drain the liquid from the beans and set aside to use later if needed.
Transfer beans to a oven-safe casserole dish.
Stir in whipping cream, tomatoes, sugar, mustard, and pepper.
Dot top of beans with butter and sprinkle with the additional 2 tbsp sugar.
Put beans in the oven at 350 degrees.
Turn the oven down to 250 degrees once the beans start to bubble.
Remove the beans from the oven once you see a 1" mark above the beans.
Test the beans for doneness. If they're too dry, add some of the reserved bean-cooking liquid. Garnish with parsley if desired.