Preheat oven to 425°F and heat your cast iron skillet over medium heat on the stove top.
In a small bowl, mix all spices together and use half of it to season the skin side of each chicken thigh.
Once the pan is heated, add 3 tbsp of olive oil, or enough to fully coat the bottom of your pan and place the chicken thighs skin side down in the pan and make sure thy aren't too crowded.
Season the bottom side of the chicken thighs with the remaining spice blend.
Let the chicken thighs cook over medium heat for 10 minutes. Make sure not to move them around the pan, just let them sit in place undisturbed for the full 10 minutes.
Without moving the chicken thighs around in the skillet, carefully remove the hot skillet from the stove top burner and place in the preheated oven. Let bake undisturbed for 10 more minutes.
After the 10 minutes are up, carefully flip the chicken thighs on to their bottoms and continue to bake for an additional 10 to 15 minutes, or until the internal temperature reaches at least 165°F.
Remove chicken thighs from oven and let rest for about 5 minutes.
Plate your delicious crispy thighs and enjoy!