Preheat the oven to 200 degrees Celsius (390 Fahrenheit).
Peel and chop the potatoes into bite-sized chunks.
Add them to a pan, cover them with water, add a pinch of salt, and boil them on a medium heat until they are fork tender.
Meanwhile, cut the sausages into bite-sized chunks.
Heat up the oil in a pan, add the sausages, and fry them until brown.
Remove the sausages from the pan and set them aside.
In the same pan, add the peeled and chopped onion and garlic, and fry them until golden.
Add the flour and whisk well, then pour over the stock, and whisk until it thickens into a gravy.
Season with salt and pepper, and add the herbs.
Once the potatoes are cooked, drain the water and transfer them to an oven-safe dish.
Top the potatoes with the cooked sausages, drizzle over the gravy, and top with cheese.
Bake for 20 minutes.
Garnish with chopped parsley.