Take the pork chops and cut envelopes into them by inserting a small, sharp knife into the side of it and carefully working it one way, remove the knife, and back in with the blade facing the other way, and working it that way. You should now have a hole on the side big enough to put your finger in, and effectively a pocket inside the pork chop. Fill the envelopes with the stuffing you've made. Sprinkle salt and pepper on the pork chops.
Put 2 T butter into the sauté pan you cooked the onions in and set on medium high heat. Braise the pork chops on both sides, making sure to sear the sides as well. Remove from pan. Put the chicken stock, the other ½ of the onion, the cider, and some salt and pepper into the pan and bring to a simmer, reducing the heat to medium. Put the pork back into the pan, as well as any runoff juices, return to a simmer, reduce the heat to low, and cook for approximately 40 minutes.