To begin, preheat your oven to 200°C. Heat the vegetable oil in a heavy pan, then brown the sausages on all sides for a few minutes. Transfer to a baking tray and roast for 20 minutes until cooked through. Continue with the mash preparation.

Place the peeled potato chunks into a large pan, cover with cold salted water, and bring to the boil. Simmer gently for 15–20 minutes until tender. Move on to preparing the onions while the potatoes cook.

In a wide pan, melt the butter over low heat. Add the sliced onions and cook slowly for 20 minutes, stirring occasionally, until golden brown and soft. Transition to building the gravy base.

Sprinkle the flour over the onions and stir until fully absorbed. Gradually add the beef stock while stirring continuously to avoid lumps. Add Worcestershire sauce, thyme, salt, and pepper. Simmer for 10 minutes until thickened. Continue with the mash.

Drain the cooked potatoes well and return them to the warm pan. Mash until smooth, then add the butter and warmed milk. Season with salt and white pepper. Keep warm while finishing the sausages and gravy.

Remove the sausages from the oven. They should be golden and sizzling with clear juices. Keep them warm while preparing to plate up.

Spoon generous portions of mash onto each plate. Top with two sausages per person. Pour onion gravy over the sausages, letting it flow onto the mash. Add a garnish of parsley if using.

Serve the dish hot with peas, cabbage, or any seasonal greens. A spoon of mustard on the side is a traditional addition that enhances the flavours.