Sweeten things up by roasting two apples, cored and cut into wedges, along with the onions and potatoes.
Heat oven to 230C/fan 210C/gas 8. In a large bowl toss the potatoes, onion, liquid and oil together. Season if you like. Tip the onion and potatoes into a large sauté pan and bake for 20-30 mins until the potatoes start to brown. Lay the chops on the potatoes and cook for 10 mins more.
While the potatoes are cooking, mix the cheese, mustard and milk together. When the chops have had 10 mins, spread the cheese mixture over them and switch the oven over to grill. Place the pan under the grill and cook for about 5 mins until the cheese is bubbling and the potatoes are golden and crispy. Serve straight from the pan.