1. Heat your oven to 170C/Gas Mark 3.
2. Fry the sausages in a large frying pan until browned then remove from the pan and put in a casserole dish.
3. In the same pan, melt the butter then fry the leeks, onion, garlic and carrots with some salt and pepper until soft then put in the casserole dish with the sausages. Cover the base of the frying pan with a small amount of water and turn the heat up until bubbling. Use a spatula to scrape any remaining meaty juices off the bottom of the pan and once the water has reduced slightly, pour it in the casserole dish with the sausages and leek mix.
4. Add the potatoes and the stock to the casserole then season and cover. Place in the oven and cook for between 1 hour and 1 hour 30 minutes.
5. Garnish with the chopped parsley and serve.