In a large bowl or zip-top bag, combine buttermilk, hot sauce, salt, and black pepper. Add the chicken and refrigerate for 1–4 hours.
In a shallow dish, combine flour, cornstarch, salt, garlic powder, onion powder, paprika, black pepper, and cayenne. Remove the chicken from the marinade, allowing the excess to drip off. Coat each piece thoroughly in the flour mixture, pressing the coating onto the chicken. Let the coated chicken rest for 10 minutes.
Heat 2–3 inches of oil in a deep skillet or Dutch oven to 350°F. Fry the chicken for 5–7 minutes per side, or until golden brown and the internal temperature reaches 165°F. Transfer to a wire rack.
In a shallow bowl, whisk together eggs, milk, heavy cream, vanilla, and cinnamon. Melt the butter in a large skillet over medium heat. Dip each bread slice into the egg mixture, coating both sides. Cook for 2–3 minutes per side, until golden brown.
Whisk together maple syrup, Dijon mustard, and hot sauce (if using).
Assemble the sandwich by placing one slice of French toast on a plate, topping with fried chicken, pickles, bacon, and cheddar cheese. Drizzle with the maple Dijon sauce, then top with the second slice of French toast. Dust lightly with powdered sugar and drizzle with extra maple syrup if desired.
Notes
For extra flavor, marinate the chicken overnight.
Adjust the level of spiciness by adding or omitting cayenne pepper and hot sauce.
Feel free to customize toppings based on personal preference.