Thoroughly dry each chicken breast with a paper towel. Place one piece between two plastic sheets or inside a large plastic bag and pound to an even thickness with a meat mallet, about ¾" thick. Repeat with the remaining pieces.

In a small bowl, combine the salt, paprika, garlic powder, onion powder, black pepper, oregano, thyme, and cayenne.

Evenly sprinkle both sides with the cajun seasoning.

Heat a large skillet over medium heat. Add olive oil, and once hot and shimmering, add the chicken breasts presentation side down. Cook for 3 minutes, then reduce the heat to medium-low. Cook until golden brown, about 2 minutes. Flip the pieces and add the butter. Occasionally baste once melted. Cook until the internal temperature reaches 160 to 165ºF (71 to 74ºC) on a meat thermometer, about 5 to 8 minutes.

Transfer to a clean plate or cutting board and let rest for 5 minutes before slicing and serving. Garnish with green onions.