TV New Clip: 'MasterChef Junior' Mystery Challenge By ETonline Staff 3:56 PM PDT, October 3, 2013 This week on MasterChef Junior, the top 12 cooks will compete in the first-ever mystery box challenge, and we have an exclusive clip!PICS: Celebs and Their Adorable KidsIn the video, the judges critique Alexander's dish -- a pan-seared filet mignon with garlic mashed potatoes, a fresh green salad, butter-glazed carrots and a spicy mixed-berry puree."You've come up with a very good dish," said Gordon Ramsay, who was particularly blown away by the creamy mashed potatoes. "Great job."Graham Elliot agreed, even going as far as comparing the 13-year-old chef to his younger self."I was nowhere near where you are at your age," Graham gushed. "I'm extremely excited to see what you keep doing as we go along."Watch an all-new MasterChef Junior Friday, October 4 at 8 p.m. ET/PT on FOX.