Devil's Food Cake is one of Mak's favourite cakes. She had a recipe for it and mixed it from scratch. She didn't use Betty Crocker's cake mix. This is a rich chocolate cake which you can't stop eating. She used sour milk which she made by mixing milk with lime juice or vinegar, and used the scum.
http://www.bettycrocker.co.uk/Our-Products/Cake-Mixes/Devils-Food-Cake-Mix
http://www.bettycrocker.co.uk/Our-Products/Cake-Mixes/Devils-Food-Cake-Mix