Pat the pork chops dry and season both sides with the salt and pepper. Heat 1 tbsp olive oil in a large skillet over medium-high heat until shimmering.
Sear the chops 3 to 4 minutes per side until deeply golden (they will finish cooking in the sauce). Transfer to a plate.
Add the remaining 1 tbsp oil to the skillet, then the apples and onion. Cook 6 to 8 minutes, stirring occasionally, until softened and lightly browned.
Stir in the garlic and sage with a pinch of salt; cook 30 seconds until fragrant.
Pour in the cider and scrape up the browned bits, then stir in the Dijon. Simmer 2 minutes until slightly thickened.
Nestle the chops back in with any juices and cook 3 to 5 minutes, until the pork reaches 145 °F in the center.
Off heat, swirl in the butter. Spoon the apples, onions and pan sauce over the chops and serve.