Illegal Burger

Launched in a cramped bar on a downtown backstreet, Illegal bears responsibility for igniting Oslo's burger frenzy. In just a few years, the restaurant expanded to a much bigger diner in trendy Grünerløkka (but thankfully kept all of its charm). The charcoal-grilled burgers are served in a retro paper wrapping like 1950s McDonald's, and they're on the small side—so you might want to order two. Aioli is the standard condiment, so make sure to ask for ketchup if that’s your preference.