Melt 2 oz. butter and saute onion until translucent (about 5 minutes). Stir in brown sugar and the tomatoes and simmer for 15 minutes. Puree in food processor, 2 cups at a time. Meanwhile, over low heat melt 2 tablespoons butter and stir in flour. Cook 5-8 minutes, stirring occasionally. Add the milk gradually, stirring constantly, and cook 12 minutes. Add tomato puree and cook until almost boiling. Then add seasonings and parsley. Enjoy!