The Hasselback potato originated in Sweden, where they were served in the hotel restaurant of the same name. Typical for Hasselback potatoes are the indentations that are filled with herbs, cheese, bacon, and so on.
Preheat the oven to 200 °C/Gas 6. Put a sheet of aluminium foil on a large baking tray.
Make several cuts into each potato with a sharp knife (be careful not to cut all the way through) and place the potatoes on the baking tray. Drizzle with olive oil and sprinkle with some salt.
Bake in the oven for 30 minutes, until the potatoes are done.
Meanwhile, cut the slices of cheese and the bacon into smaller cubes.
Take the potatoes out of the oven and put a strip of cheese, bacon, and a sprig of thyme in several indentations.
Return to the oven for another 5–10 minutes until the cheese has melted.
Meanwhile, make the topping: peel and chop the onion, cut the bacon into smaller pieces. Fry the onion and the bacon together until the bacon is crispy. Mix together with the sour cream. Season with pepper
Serve warm or at room temperature together with the topping. Sprinkle with some fresh thyme.