1. Heat your oven to 160C/Gas Mark 3.
2. Place a casserole dish over a medium heat with a little of vegetable oil and then throw in your pork chops with a little seasoning of salt and pepper to get a little colour on the outside of your chops, just a light brown colour. This should only take a minute or two. Once browned, turn the heat off.
3. Place the pork chops in a single layer at the bottom of your casserole dish. Roll your sage leaves up and chop finely and add to the pork chops along with the leaves from your thyme sprigs.
4. Cover with the sliced onion and apple and ensure it is evenly spread across all the chops.
5. Make up your stock then stir the mustard into it and pour over the chops.
6. Place a lid on the dish and cook for 1 hour 30 minutes, or until the pork is tender.
7. Take a few ladles of your liquid into a saucepan and over a high heat, reduce it to a thicker sauce.
8. To serve, place 1 pork chop per person in a bowl with a tablespoon of the onion/apple mix and pour over a little of your thickened sauce. Serve with your favourite vegetables and creamy mashed potato.