Preheat the oven to 180 degrees top / bottom heat.
Cut a lid off the stalk side of the washed apple. Remove the core, scoop out the pulp with a spoon and place in a bowl. Rub the inside of the apple with lemon juice and drizzle the hollowed out pulp with it.
Cut the cleaned mushroom into small pieces and add to the pulp. Cut the rind from the camembert and chop the cheese. Mix with the pulp and mushrooms and season with salt and pepper.
Pour the mixture into the apple. Place the apple in a buttered dish. Place the cut apple lid next to the apple in the tin. Bake in the oven for about 20 minutes, the cooking time may vary.
Arrange the baked apple on a plate, garnish and serve.