Preheat oven to 350° F.
In a large oven-safe skillet, such as a cast iron skillet, heat the butter over medium heat until melted. (If you do not have an oven-safe skillet, you can transfer the pork chops to a baking dish when you're ready to bake them.)
Add the onion, celery and apple to the pan. Cook, stirring often, for 7-8 minutes, until softened.
Add the garlic and sage to the pan and cook, stirring, for 30 seconds. Transfer the contents of the skillet to a medium bowl. Stir in the panko breadcrumbs and season with salt and pepper to taste.
In a small bowl, stir together the garlic powder, onion powder, ¼ teaspoon salt and ¼ teaspoon pepper.
Pat the pork chops dry. Use a knife to cut a pocket into the side of each pork chop, as big as you can but being careful not to cut all the way through to the other side, and leaving the ends of the pork chops intact.
Rub the seasoning mixture over both sides of the pork chops. Then spoon the apple breadcrumb filling into the pocket of each pork chop. You may not use all of the filling; don't overstuff the chops or they won't close. Secure the pork chops closed with toothpicks.
Wipe out the skillet that you used to sauté. Heat the olive oil over medium heat. Add the pork chops to the hot pan and brown on both sides, 2-3 minutes per side. Sprinkle the pork chops with the chopped rosemary.
Transfer the skillet to the preheated oven and bake for 8-15 minutes, until the center of the thickest part of the pork chops registers 145° F. (If using bone-in pork chops, they will take a few minutes longer to cook through.) Let pork chops rest for 3-5 minutes and then serve.