Cut the pork fillet into strips about 3cm thick. Place flour in a shallow dish. Season with salt and pepper. Dip the pork into the flour, so it's lightly coated. Shake off any excess flour. Heat olive oil in a flameproof casserole dish, over a medium-high heat. Once heated, add the pork in small batches and cook for 2 - 3 minutes, until browned on all sides. Transfer browned pork to a plate and set aside. Turn the heat down to medium - low. Add the onions and carrots to the pan and cook gently for about 5 minutes, stirring occasionally. Add the pork and spices to the pan and cook for a further 30 seconds, until all the ingredients are coated with the spices. Add the stock and bring to the boil. Turn the heat down, place the lid on top and simmer gently for 15 minutes.
Cut the apples into quarters and remove the core (leave the skin on). Add apple to the pork and vegetables. Stir gently and then replace the lid. Continue cooking for another 15 minutes, until the pork is cooked through.
To serve: Remove the cloves and cinnamon stick. Serve the apple and pork tagine with a large green salad and couscous.