Place chicken breasts in a bowl and cover with pickle juice. Marinate for at least 4 hours, or preferably overnight.
In a shallow dish, whisk together flour, powdered sugar, salt, pepper, paprika, garlic powder, onion powder, and cayenne pepper.
Remove chicken from pickle juice and pat dry with paper towels.
Dip each chicken piece into the flour mixture, ensuring it is fully coated.
In a large skillet or Dutch oven, heat about 2 inches of peanut oil to 350°F (175°C).
Carefully place coated chicken pieces into the hot oil, being careful not to overcrowd the pan. Fry for 6-8 minutes per side, or until golden brown and cooked through (internal temperature reaches 165°F or 74°C).
Remove chicken from oil and place on a wire rack to drain.
While chicken is frying, spread butter on the cut sides of the brioche buns and toast them lightly in a skillet or under the broiler.
Assemble the sandwiches: place a piece of fried chicken on the bottom half of each toasted bun, top with dill pickle slices, and cover with the top half of the bun.
Notes
For best results, use peanut oil for frying as it has a high smoke point and imparts a subtle flavor.
The powdered sugar in the flour dredge adds a slight sweetness and helps with browning and crispiness.
Ensure the oil temperature remains consistent for even cooking and a crispy crust.
This recipe is a great option for those looking for homemade fast food or a crispy chicken sandwich recipe.