Today's going to be short for me, because my book is set in modern day NYC, which means the food, drink, holidays, and culture are all common knowledge. There is one thing to add, though. A food: human hearts.
In my book, when a devil or demon consumes a human heart, they gain magical strength from it. The demons, being chaotic and much more animalistic (Spell check says this isn't a word. Lame.) than devils, love ripping the hearts out and gobbling them up raw and bloody. Devils wrote a book 101 Things To Do With Human Heart, a cookbook with various glazes and culinary techniques to make heart scrumptious.
That's all for today. Tomorrow is the grand finale of the Worldbuilding Blogfest, so don't miss it!