Blackened Chicken Sandwich

Place 4 medium boneless, skinless chicken cutlets in large container. Add 1 cup pickle juice to container, covering chicken completely.
Secure lid on container and place in refrigerator. Marinate chicken 1 hour minimum, up to 8 hours.

While chicken marinates, add ½ cup mayonnaise, 1 teaspoon Cajun seasoning, ½ teaspoon smoked paprika, ½ teaspoon garlic powder, and 1 dash hot sauce to medium mixing bowl. Stir all ingredients together until fully incorporated into smooth mixture.
Cover bowl with lid or plastic wrap and refrigerate until ready to serve.

After chicken has marinated for desired length of time, remove chicken from container, pat each cutlet dry on all sides with paper towels, and place cutlets on large plate.
Season cutlets on all sides with 1 tablespoon blackened seasoning. Set aside.
Place large cast-iron skillet on stovetop over medium heat. Add 1-2 tablespoons neutral-flavored oil to skillet and continue heating pan until oil is hot and shimmery.
When oil is hot, place chicken cutlets in skillet, being careful not to crowd pan. Cook chicken in 2 batches if needed.
Cook chicken 3 to 4 minutes, then flip chicken over and cook 1 to 2 minutes more, until chicken reaches 158° to 160° Fahrenheit internally.
Cover each chicken cutlet with 1 slice of Swiss cheese (4 slices Swiss cheese total). Cook chicken 1 additional minute or until cheese is melted and internal temperature of chicken is between 160° and 163° Fahrenheit.
Once cheese has melted, transfer chicken cutlets to cutting board and set aside. Repeat with any remaining cutlets.

Once all chicken cutlets have been cooked and transferred to cutting board, place second large skillet on stovetop over medium-high heat. Add 2 tablespoons unsalted butter to skillet and let butter melt completely, swirling and tilting pan as needed to distribute butter across entire surface of pan.
When butter has melted, place tops of 4 brioche buns cut-side down in skillet. Toast bun tops 1 to 2 minutes, until cut-side of buns are golden and just crisp.
Transfer toasted top buns to cutting board or serving plates and set aside.
Add 2 tablespoons unsalted butter to skillet and let butter melt completely.
When butter has melted, place bottoms of 4 brioche buns cut-side down in skillet. Toast bun bottoms 1 to 2 minutes, until cut-side of buns are golden and just crisp.
Transfer toasted bottom buns to serving plates.

Spread prepared Cajun mayo over toasted side of bottom bun, then top mayo with desired number of dill pickle slices.
Place one chicken cutlet on top of pickle slices.
Spread prepared Cajun mayo over toasted side of top bun, then place top bun on top of chicken, mayo-side down.
Repeat with remaining ingredients. When all sandwiches have been assembled, serve warm with fries, chips, or other preferred sides.