Plan ahead the chicken needs to marinate for 8 hours or up to 24 hours. Although I have used 2 tablespoons Louisana hot sauce, you can add in more if desired, trust me the chicken will not be overly spicy!
In a large bowl mix together buttermilk, oil, hot pepper sauce, Dijon mustard, fresh garlic, 1 tsp salt and black pepper (I use about 1/2 tsp freshly ground black pepper) whisk to combine well, then add in the onion.
Add in the chicken pieces and turn to coat thoroughly with the mixture.
Cover and refrigerate for 8-24 hours, turning the chicken pieces occasionally.
Place a rack (I use a cookie rack, it fits perfectly!) on a 15 x 10-inch baking sheet.
In a bowl mix together breadcrumbs, Parmesan cheese, flour, thyme, paprika, cayenne and 1 teaspoon salt.
Remove the chicken from the marinade (discard marinade) letting any excess to drip off (do not leave any onions slices on the chicken, discard with marinade).
Add in the chicken pieces to the breadcrumb mixture, and turn to coat the chicken evenly on all sides.
Arrange the chicken on the rack that is on the baking sheet (skin side up).
Let stand for around 30 minutes.
Set oven to 425° (let oven heat up for 10 minutes, oven must be HOT!).
Drizzle the melted butter on top of the chicken pieces.
Bake until crisp and golden brown about 45-50 minutes.