Preheat oven to 190°C.
Heat the butter in a large fry-pan over medium heat; when melted, pour off 1 tablespoon of the butter and reserve.
Return fry-pan to the heat; add onion, celery and apple and sauté, stirring occasionally until translucent.
Stir in the sage, thyme, oregano, parsley and pepper and cook until just fragrant, about 1 minute.
Turn the mixture into a large mixing bowl. Add the bread cubes, egg, stock and salt and toss gently to distribute ingredients evenly.
Tip the mixture into a Large GLAD Oven Bag and place in a loaf pan, easing the stuffing to fit the contours of the pan.
Drizzle the reserved melted butter over the top of the stuffing, then tie close. Pierce 6 holes in the top of the bag to allow steam to escape.
Place the loaf pan in the middle of the oven. Bake for 25 minutes, then open the oven bag and turn back to expose the top of the stuffing; trim bag if necessary.
Return to the oven, checking the bag is away from the oven walls and cook for another 15 – 20 minutes until a golden crust forms.