Chicken, Bacon and Mushroom Potato Pie

I made this for my parents a couple of weeks ago. I liked it but the sauce split. I'm not sure why. It was pretty tasty though, I like potatoes as the pie crust.

Chicken, Bacon and Mushroom Potato Pie (from Let The Baking Begin)
(Serves 4)

1.35kg potatoes, sliced thinly
2 chicken breasts
300g button mushrooms, quartered
4 strips thick cut bacon, cut into ⅓ inch pieces
½ large onion, chopped
30g grated cheese
125ml stock
60ml single cream
salt and pepper, to taste
garlic powder

Heat a frying pan over medium heat, add the chopped bacon and render the bacon until it crisps up. Add the chopped onions to the bacon and continue cooking until the onion is golden in colour. Tilt the frying pan to the side allow the fat to drip to the bottom and remove the onion and bacon to a separate bowl.

Heat the frying pan on high with the bacon fat in it, add the mushrooms and brown them over high heat, stirring frequently. Remove from the heat. Add the salt, pepper and garlic powder, mix to coat.

Cut the chicken breast into 1 inch pieces. Add the salt, black pepper and garlic powder and toss to coat.

Layer the ingredients in the following order: chicken, half of bacon and onion mixture, light sprinkling of cheese, mushrooms, bacon and onion mixture, a little bit of salt and pepper to season the mushrooms, light sprinkling of cheese and lastly arrange most of the potatoes on top.

Mix the chicken stock and cream and pour on top. Cover the baking dish with foil or lid. Place into preheated to 220C oven and bake for 15 mins, then reduce the heat to 180C and bake for another 40 mins. Remove the foil or the lid and cook for additional 20-30 mins or until the top is golden brown. Serve.