This is a rich vanilla flavour that has no Acetoin, Acetyl Propionyl, or of course, Diacetyl. Instead it uses a lesser known custard note called Butyric Acid. 
This is the ingredient that other flavour companies are now using to replace Acetoin and Acetyl Propionyl for flavours like Vanilla Custard.
Butyric Acid is found in milk, butter, and cheeses. In fact, Butyric Acid occurs at about 2.9% in butter.
Butyric Acid is a healthy addition to foods, and a good article about this can be found here 
http://www.livingthenourishedlife.com/2010/10/is-butter-healthy-part-one-butyric-acid
Ingredients: Natural and Artificial Flavours, Propylene Glycol, Ethyl Alcohol