COOK potatoes in boiling water 20 to 30 min. or just until tender; drain. Cool 10 min.
MEANWHILE, whisk next 3 ingredients until well blended. Heat oil in large skillet on medium heat. Add bacon and onions; cook and stir 4 min. or until onions are crisp-tender. Stir in flour, sugar and pepper. Gradually stir in dressing mixture. Cook 1 min. or until bubbly and thickened.
SLICE potatoes. Add to ingredients in skillet; cook 3 to 5 min. or until heated through, stirring frequently. Top with parsley.