Heat the olive oil in a small frypan and add the diced onions. Cook, stirring frequently until they soften then remove from the pan and place into a bowl.
Cut the potatoes into halves then carefully scoop out the inside, leaving a 10 mm thick skin.
Combine the scooped out potato with all the ingredients then fill each potato with the mixture. Bake in the oven at 180°C until golden.