Preheat oven to 425 degrees.
Core the apples and thinly slice.
Heat non stick, oven safe skillet over medium high heat. Add the oil.
Add the pork tenderloin and cook until both sides are browned, about 5 minutes total. Remove the tenderloin to a plate.
Reduce heat to medium and add the butter to melt. Add the apple slices and cook for a couple of minutes.
Pour in the apple cider and whisk in the honey, mustard, salt, thyme and pepper.
Return the browned pork tenderloin to the skillet with the apple slices and sauce.
Place the skillet in the oven and bake for 15 - 20 minutes, or until internal temperature reaches 145 degrees. Remove the skillet from oven and allow the pork to rest for 10 minutes before slicing and serving