Marinating the Chicken
Cut the chicken thighs into rough squares about the size of the buns you're using.
Whisk the buttermilk and egg together in a resealable container and add the chicken thighs. Seal and refrigerate for 4 hours or overnight.
Dredging the Chicken
Preheat oven to 400F.
Transfer the chicken thighs to a wire rack or tray. Let any excess marinade drip off the chicken. Discard remaining marinade.**
Mix the flour and dry spices together in a shallow bowl.
Place a chicken thigh in the flour/spice mixture and toss to coat. Place the coated chicken back on the rack or tray and repeat until little to no flour remains.
Pan Frying the Chicken
Heat a large oven-safe skillet over medium heat with the olive oil. (I used a 12" cast iron skillet.)
Once the oil is hot, carefully place the chicken thighs in the skillet. Cook for 2.5-3 minutes or until the bottoms are golden brown before flipping and cooking another 2 minutes. Transfer the skillet to the oven and bake for 8-10 minutes or until the chicken reaches an internal temperature of 165F.
Transfer the cooked chicken to a clean cooling rack to rest.
Place the skillet back over medium heat to toast your buns before serving.