In a saucepan, cook the potatoes whole and unpeeled for twenty-five minutes.
Cut the onion and mushrooms. Peel the prawns completely and chop them. Set aside.
Cut the potatoes in half and empty them, keeping the inside in a bowl.
In a frying pan, cook the onion, mushrooms and prawns. Add the potato, cream, salt, pepper and cheese. Mix together.
Fill the hollowed out potatoes with the resulting mixture and bake in the oven for ten minutes.