Combine all the dry spices in a small bowl: garlic powder, onion powder, paprika, oregano, basil, thyme, cayenne pepper, salt, black pepper, and cumin. Stir well to ensure the spices are evenly distributed, breaking up any clumps. This creates your blackening seasoning base that will adhere beautifully to the chicken.

Pat the chicken thighs dry with paper towels—this is essential for achieving a proper crust. Generously coat all sides of each thigh with the blackening spice blend from Step 1, pressing the spices firmly so they adhere to the meat. Don't be shy; you want a thick, flavorful crust that will char beautifully.

Place a large cast-iron or heavy-bottomed skillet over medium-high heat. Add the avocado oil and butter together, allowing them to heat until the butter is fully melted and the mixture just begins to shimmer and smoke slightly (about 2-3 minutes). This high smoke point combination is crucial for developing that signature blackened crust without burning the spices.

Carefully place the seasoned chicken thighs skin-side down in the hot oil-butter mixture. Resist the urge to move them—let them sit undisturbed for 5-6 minutes until a dark, caramelized crust forms on the bottom. I find this patience is what separates good blackened chicken from great blackened chicken; the stationary heat creates that coveted char.

Flip the chicken thighs carefully and cook on the second side for 4-6 minutes, depending on thickness, until the internal temperature reaches 160°F when measured with a meat thermometer inserted into the thickest part. The second side will develop a crust as well, though it may be slightly less dramatic than the first side. Let the cooked thighs rest in the pan for 1-2 minutes before serving to redistribute the juices.