Place the chicken thighs in a large bowl.
To your chicken add all of your seasoning for the wet batter: buttermilk and spices. Using your hands (they’re your best utensil!) mix together the chicken until everything is throughly combined. Clingfilm the bowl and place your chicken to marinate in the fridge for a minimum of 4 hours.
In a shallow dish, add the ingredients for the dry batter: flour, seasonings, cornstarch and bicarbonate of soda. Whisk this together.
Heat up a frying pan with some sunflower or rapeseed oil on a medium heat.
Remove your chicken from the fridge and dip each chicken strip into the dry batter. Shake off any excess and drop straight into the hot oil. Fry 1-2 at a time until they are golden and crispy, about 5-6 minutes on each side. If they brown too quickly turn the heat down. Be sure not to overcrowd the pan.
Drain on paper towels!
Spread some butter on the brioche buns and toast in a pan.
Spoon some spicy mayonnaise onto the bottom bun, then add romaine lettuce, pickles, the fried chicken and cheese. Be sure to add a generous amount of spicy mayo on the top bun too! And there you have the ultimate fried chicken burger!