Place tomato halves, cut side up, in a 12- x 8- x 2-inch baking dish. Combine sugar, salt, and pepper; sprinkle evenly over cut surface of each tomato half.
Combine breadcrumbs, butter, and parsley, tossing well. Sprinkle breadcrumb mixture evenly over cut surface of each tomato. Pour 1/2 inch water around tomatoes in dish. Bake at 350° for 20 minutes or until breadcrumbs are lightly browned. Transfer to a warm serving platter. Serve warm.