Season pork with salt and pepper.
Let stand for 30 minutes if possible - or wrap and store in the refrigerator overnight. You can skip this step but it does make the meat more flavorful.
Stir together brown sugar, dijon mustard, herbes de provence, and bourbon. Rub mixture all over pork.
Heat oil in a heavy skillet over medium heat and brown the pork on all sides.
Add apples and onion and cover. Turn heat to low.
Cook until apples are tender and pork is done, stirring the apples and onions occasionally. This will take about 15 minutes. Current practice is for the pork to be a little pink in the center - 145F with an instant-read thermometer. This will ensure it's tender and juicy.
Let stand 5 to 10 minutes before slicing. Garnish with fresh parsley or thyme.
