For a week starting Monday, Prime's offering its new steakhouse burger for only $5 (regular $15); made from steaks hung 40 days in Prime's Himalayan-salt-tiled dry-aging room, the meat-wich comes on a potato bun, and's topped with smoked-bacon mayo, crispy fried onions, and garlic spinach -- finally, a lunch Popeye and J. Wellington Wimpy can agree on.