HEAT oven to 400ºF.
TOSS potatoes with oil and 3 Tbsp. Parmesan; spread onto bottom of 15x10x1-inch pan sprayed with cooking spray. Bake 20 min. or just until tender.
MEANWHILE, cook bacon in large nonstick skillet on medium heat 4 min. or until crisp. Remove from pan. Drain all but 2 Tbsp. drippings from skillet. Crumble bacon; return to skillet. Add white onions; cook and stir 3 min. Stir in apples; cook 3 to 4 min. or until crisp-tender, stirring occasionally.
ADD potatoes to ingredients in skillet; cook 10 min., stirring occasionally. Spoon into serving dish; top with sunflower kernels, green onions and remaining Parmesan.