Preheat the oven to 392ºF. While the oven heats up, wash and dry the potatoes.
Next, wrap the potatoes individually in kitchen foil and bake for one hour.
After this time, having pricked them and checked that they are soft, remove the potatoes from the oven and allow them to cool, then cutting them in half.
While the potatoes cool, slice the bacon into small pieces and fry with two tablespoons of olive oil until golden.
Empty the potatoes using a spoon. Mash using a fork and mix with the remaining oil to make a paste. Season.
Next, add the bacon and grated parmesan cheese. Stir well to mix all the ingredients and fill the potatoes.
Place the potatoes on the oven tray again and sprinkle with grated emmental cheese. Bake for 20 minutes to melt the cheese.
Remove from the oven and decorate with rosemary leaves.