Preheat the oven to 400°F. Using a sharp knife make a horizontal cut into the thick side of each chicken breast slicing almost all the way through but not completely.
Stuff each chicken breast with a slice of mozzarella sun-dried tomatoes and asparagus. Season with a pinch of salt and pepper. Press the edges together and secure each breast with a toothpick.
In a small bowl combine oregano thyme smoked paprika garlic powder onion powder 1 1/4 teaspoons salt and 1/4 teaspoon black pepper. Rub this spice mixture evenly over the outside of the chicken breasts.
Heat the olive oil in a large ovenproof skillet preferably cast-iron over medium-high heat. Add the chicken and cook until golden brown about 4 minutes per side turning once.
Transfer the skillet to the preheated oven and bake until the chicken is cooked through and registers 165°F on an instant-read thermometer about 8 to 10 minutes.
Add the butter and lemon juice to the skillet. Swirl until the butter melts approximately 30 seconds. Remove the toothpicks from the chicken.
Divide the chicken among serving plates and spoon the pan sauce over each portion.