HEAT oven to 400ºF.
TOSS potatoes with oil and 3 Tbsp. Parmesan; spread onto bottom of rimmed baking sheet sprayed with cooking spray. Bake 20 min. or until tender.
MEANWHILE, cook bacon in large skillet until crisp. Remove bacon from skillet, reserving 2 Tbsp. drippings in skillet. Drain bacon on paper towels. Add white onions to skillet; cook and stir 3 min. Stir in apples; cook 3 to 4 min. or until crisp-tender, stirring occasionally. Crumble bacon; return to skillet.
ADD potatoes to skillet; cook 10 min., stirring occasionally. Spoon into serving dish; top with sunflower kernels, green onions and remaining Parmesan.