I recently got a new job at the Cinemas and one of my jobs is making popcorn.. one thing we put in it is flavocol. The ingredients said 'artificial' butter flavor.. but I was still concerned as to weather is was 'Vegan' or not.. so I did a little googling and i founnd.. http://www.foodaq.com/html/General/43068.html
Flavacol is an accidentally vegan butter flavored salt. It's the same stuff the movie theaters use on their popcorn! It's really strong when sprinkled on foods but when you cook with it the flavor mellows and leaves a hint of butter that's normally hard to obtain from other sources. In that particular recipe using the Flavacol masks the yeastiness and accentuates the cheese taste.