Preheat the oven to 220 degrees celsius.

Heat the 15 ml margarine in a heavy-based saucepan and fry the mushrooms for approximately 3 minutes. Add the bell pepper and fry for 2 minutes until the pepper is soft.

Remove the mushrooms and bell pepper and keep aside.

Place the 100 g margarine in the saucepan and let it melt over low heat. Stir in the cake flour and then gradually stir in the milk. Stir continuously until the sauce is thick and smooth.

Add the salt and pepper and let the sauce cool.

Add the sherry to the white sauce and mix well. Add the mushrooms, bell pepper and chicken and stir to mix. Transfer the mixture to an oven-proof dish.

Roll out the puff pastry and cut out a shape to fit over the oven-proof dish. It should be slightly larger than the container.

Cover the dish with the pastry and trim the edges. Decorate the pie with pastry shapes of your choice and prick the crust a few times.

Brush the crust with the whisked egg and bake the pie for approximately 20 minutes until the crust is golden brown and cooked.