Meanwhile, add the sliced onions to a frying pan, along with the butter and oil. Cook over a medium-low heat for at least 10 minutes (longer is better), until softened. If you have more time, you can caramelise them fully by cooking over a very low heat for a long time (up to an hour or so).

Cook the vegetarian hot dogs according to the instructions on the packet. Mine needed to be boiled for 15 minutes.

When everything is ready, assemble the hot dog baked potatoes. Cut the potatoes in half, add some sautéed onions and a sausage, and finish with your favourite hot dog toppings.