Sirloin Steak in Parmesan-Peppercorn Sauce

1/2 cup KRAFT LIGHT DONE RIGHT! Zesty Italian Reduced Fat Dressing, divided 1 lb. well-trimmed boneless beef sirloin steak 1/3 cup Fat Free Sour Cream 4-1/2 tsp. KRAFT 100% Grated Parmesan Cheese 1/4 to 1/2 tsp. black pepper 1 large onion, thinly sliced POUR 1/4 cup of the dressing over steak in resealable plastic bag. Seal bag; turn to coat. Refrigerate 30 min. or overnight to marinate. Combine sour cream, 2 Tbsp. of the remaining dressing, the Parmesan cheese and pepper. Refrigerate until serving time. HEAT remaining 2 Tbsp. dressing in large nonstick skillet on medium heat. Add onions; cook 7 to 8 min. or until golden brown, stirring frequently. Remove onions; set aside. DRAIN steak; discard marinade. Cook steak in same skillet on medium heat 3 to 4 min. on each side for medium doneness. Place on cutting board; slice crosswise into thin strips. Serve steak topped with sauce and onions. esta fue mi cena hoy con fresh green beans Titi Vane