Prep Work: Chop carrots, celery and onion; store together. Chop tomatoes and greens; store together. Soak and cook beans the day before if desired.
Chop all vegetables. Heat frying oil in large soup pot and saute carrots, celery and onion over medium heat for 5 min.
Add broth, rinsed beans, tomatoes, mustard greens, sugar, pepper and 1/2 of the parsley. Bring to a boil, then take off lid and reduce heat to simmer for approx. 30 min.
OPTIONAL: To add dumplings for yield of 6, combine 1 c. flour, 1/2 tsp baking powder, 1/2 tsp. salt, and 1/2 c. milk. Stir milk into dry ingredients just until combined, then add remaining 2 Tbsp. of chopped parsley (or substitute with cilantro). Drop by rounded teaspoons into simmering soup during the last 10 min. and top with lid while simmering.