In a shallow dish, whisk together all the seasonings: paprika, cumin, cayenne pepper, thyme, onion powder, garlic powder, kosher salt, and black pepper.
Dry chicken breasts with paper towels and coat with two tablespoons of canola oil on both sides. Toss both sides in the seasoning mixture, pressing with your fingers to help the coating adhere.
Heat a large cast iron skillet over high heat until smoking hot, for about 5 minutes. Add just about 1 tablespoon of canola oil and brush it well all over the skillet.
Add the chicken breasts and cook for about 30 seconds on each side to blacken, then transfer the skillet into the oven to finish cooking, for another 12-15 minutes. Chicken should be no longer pink in the center and the internal temperature should reach 160 degrees F.
Remove chicken to a platter, cover with foil and allow to rest for 5 minutes before slicing and serving.
