Preheat the oven to 200ºc/400ºf. Rub the Maris pipers with oil and season well with salt, then pop on a tray and put into the oven for 60 minutes.
Meanwhile, thinly slice the bacon and render out the fat in a pan, putting it in cold and allowing it to heat up gradually.
Pour the bacon (reserve 1 tbsp) and the fat into a bowl and mix in the garlic and herb cheese. Throw in the dijon mustard.
Cut the top of the potato with 3 slices into a star, then fill the slices with the cheese and bacon mixture.
Mix the grated garlic with the melted butter, tsp chopped chives and season. Use this to pour all over the potato.
Return to the oven for 15 minutes to get the cheese molten, then pour over the butter from the tray, sprinkle over the bacon bits, chives and the sour cream and serve.
