Chicken and Mushroom Pot Pies

I found this recipe in a Coles supermarket quarterly magazine. My two girls love any kind of pies - sweet or savoury. Quick and easy to cook.

1 tbsp oil
1 leek, halved and sliced
4 pieces of chicken thigh fillets, removed skin and chopped to bite pieces
2 medium sized potatoes, peeled and chopped
1 carrot, chopped
1 cup frozen peas
300gm cup mushrooms, halved (the ones I bought were about medium size)
1 1/2 cups chicken stock
1/2 cup cream
1 tbsp gravy powder (I used Gravox)
2 sheets of frozen puff pastry
1 egg yolk, lightly beaten

1. Heat the oil in a large frying pan on medium. Add in leeks and cook for 5 mins until soft but not brown.
2. In a separate saucepan, boil some water to cook the chopped carrots and potatoes. 
3. Increase heat to high, add the chicken and cook for 3-5 mins, stirring until brown. Add in the mushrooms, potatoes and carrots and cook for 2-3 mins, until mushrooms are soft.
4. Add the chicken stock and peas and bring to boil. Reduce heat to low and simmer for 5 minutes.
5. Stir in the cream and simmer for another 2 minutes. Mix together the gravy powder and some water. Add to chicken mixture and simmer for 2-3 mins, until thickened slightly.
6. Spoon the mixture into 4 x 1-cup ramekins.
7. Heat the oven to 180C (fan-forced). 
8. Cover the filled ramekins with the puff pastry (cut into rounds), pressing the edges to seal.
9. Make a slit in the centre for the steam. Brush with the egg wash. Bake for 15-20 minutes until puffed and golden.