Cut the potatoes lengthwise without reaching the bottom of the knife. Salt them very well, add the olive oil together with the rosemary and bake them at 220 degrees in a dry oven for 40 minutes. 

Put the chopped bacon in a pan sauté it. 
In a bowl add the sour cream, zest and juice of a lemon, salt and pepper. Stir until the mixture sets. 

For the setting, put the sour cream, the bacon and at the end put the chopped chives on top of the potato. 

TIPS 
Lemon juice hardens the cream faster.