Combine the kosher salt, smoked paprika, dried thyme, onion powder, garlic powder, cayenne pepper, cracked black pepper, and dried oregano in a small bowl. Mix thoroughly so the spices are evenly distributed. This blend is the foundation of your blackened crust, so take a moment to ensure there are no clumps, especially from the paprika and garlic powder. Set aside.

Pat the pounded chicken breasts dry with paper towels—this is crucial for achieving a proper sear and crust. Brush both sides of each chicken breast lightly with avocado oil. Press the spice blend generously onto both sides of each piece, using about half the mixture per side. I like to press the spices firmly so they adhere to the surface and create that characteristic blackened texture rather than just dusting them on. Let the seasoned chicken sit at room temperature while you heat your skillet.

Preheat your oven to 450°F. While it preheats, place a cast iron or heavy-bottomed stainless steel skillet over high heat for about 5 minutes. You want the pan extremely hot—this high temperature is what creates the characteristic dark, crusty exterior on blackened chicken. The skillet is ready when a drop of water immediately sizzles and evaporates on contact.

Carefully lay the seasoned chicken breasts in the hot skillet without moving them—resist the urge to fidget with them! Sear for about 30 seconds on the first side to develop that blackened crust, then flip and sear the second side for another 30 seconds. The spices should turn dark and fragrant, creating a caramelized exterior. Don't worry if the spices look very dark; that's exactly what you want. Work quickly since you only need a minute total.

Transfer the seared chicken directly from the skillet to a baking sheet or leave it in the skillet if it's oven-safe. Place in the preheated 450°F oven for 10-12 minutes until the internal temperature reaches 165°F when checked with a meat thermometer at the thickest part. I always use a thermometer here rather than guessing—it ensures juicy, perfectly cooked chicken every time without any dry spots.

Remove the chicken from the oven and let it rest on a cutting board for 5 minutes before slicing or serving. This resting period allows the juices to redistribute throughout the meat, keeping it moist and tender rather than having them run out onto your plate. Slice against the grain if desired and serve immediately.