Peel and chop the potatoes. Cover them with cold water, season generously with salt and then bring it to the boil. Simmer until tender, then drain them and leave to steam dry.
Preheat the oven to 200C (fan).
Meanwhile, cut the sausages in half, then pan fry them until they stary to brown.
Add in the sliced onions and cook until they start to caramelise. This could take about 10 minutes.
Chuck in the garlic and cook for a minute, then sprinkle in the flour. Stir well and cook for a further minute.
Pour in the beef stock, then bring it to the boil, and cook, stirring often, until it starts to thicken.
Add the Worcestershire sauce, and frozen peas, then taste for seasoning.
Transfer it to a deep oven proof dish.
Mash the potatoes, then add the butter and milk then stir until it’s smooth. Taste for seasoning.
Spoon the mash over the top of the sausages, then smooth it over. Scatter the cheese over the top, then bake it until it’s golden and bubbling.
Leave it to stand for a minute before serving. Serve with extra gravy and some veggies.
Enjoy.