Preheat the oven to 200°C (400°F).
Place the sausages on a baking sheet and bake for 25-30 minutes.
Peel and chop the potatoes into even chunks.
Boil the potatoes in salted water for 15-20 minutes until tender.
Drain the potatoes and return them to the pot. Add butter and milk.
Mash the potatoes until smooth and creamy. Season with salt and pepper.
Slice the onion thinly and sauté in a pan until golden brown.
Sprinkle flour over the onions, stirring to combine and cook for a minute.
Gradually add the stock, stirring constantly until thickened.
Once the sausages are done, serve them over mashed potatoes with gravy poured on top.
