Unfortunately I can't travel and join the yearly New Orleans festival since I'm broke, have to work, and...am broke. But I can think over books I've read that are set in New Orleans or have that Mardi Gras feel in time for the end of the Mardi Gras festival. We can't all celebrate at the actual events in life, but just to acknowledge they're going on helps us be able to partake in the events too, just a bit. Hey, it's a theory!
Really keeps the family and all who know her in terror? Check.
Acts like a grandmother who makes cookies like Carol on the Walking Dead is known for her cookies? Check.
Has creepy mad science projects in the basement? Check
Is so bad-ass and creepy she has the reputation of the top priestess for the entire west coast or whatever? Uber check.
We can't leave out one of the series people think of most - Interview with Vampire. Lestat, Louis and others have made their home in New Orleans amidst flashy clothes and luxury. I haven't read all the books myself, but even I know a little about the story.
Sookie Stackhouse doesn't have a far trip to go from her hometown of Shreveport, Louisiana to venture into New Orleans territory, but she does a few times. While there the author doesn't touch on the culture or anything unique seeming about the city, so it's easy to forget about.