Combine the Spice Mix ingredients in a small bowl. (If you like your chicken with a kick, add the full teaspoon of cayenne pepper.)
Add half of the Spice Mix to the buttermilk in a gallon-sized Ziploc bag. Then Add chicken thighs and marinate overnight or up to 24 hours.
To Cook
Preheat your oven to 350 degrees F.
Combine the remaining Spice Mix with the bread crumbs and flour in a shallow bowl. In another shallow bowl, whisk the eggs and milk together.
Remove chicken from the buttermilk, shaking off the excess marinade. Dip chicken thigh first into the egg wash and then cover in bread crumb mixture, shaking off excess breading. Place the thigh onto a baking sheet and repeat with the remaining chicken thighs.
Bake for 45 minutes or until deep golden brown and the juices run clear when the chicken is pierced. Serve immediately.