Chicken Mushroom Pie with Duchess Potato lid

Instructions

1. Brown mushrooms, remove, sear chicken (aggressively!) in same pan, cut into large pieces. Sauté bacon, onion and garlic, deglaze with Guinness, make roux, add stock, simmer with mushrooms to thicken (~10 min). Add chicken towards end. Pour into a baking dish, pipe on mashed potato, finish with butter and parmesan, bake 30 min.
2. Garlic butter mushrooms - Melt 1/4 of the butter in a large 30cm/12" non stick pan over high heat. Add mushrooms, toss for 3 - 4 minutes until you get some browning on the surface. Add another 1/4 of the butter, melt, toss to coat. Add 1/4 tsp each salt and pepper and half the garlic, toss 30 seconds until garlic is golden - mushrooms will still be hard inside, they finish cooking later. Remove into bowl (make sure you scrape out all garlic bits).
3. Sear chicken - Sprinkle the chicken with 1/2 tsp salt and 1/4 tsp pepper. In the same pan, melt another 1/4 of the butter until hot and foamy. Sear chicken 2 minutes on each side until nicely golden but inside is still raw (if they don't fit in a single layer, do in batches). Remove onto plate, once cool enough to handle cut into 2.5cm (1") pieces.
4. Bacon and onion - In the same pan, add bacon and stir for 15 seconds, then add the onion (there should be enough fat from the chicken). Cook for 2 minutes until the onion edges are golden and starting to soften. Add remaining garlic and stir 20 seconds.
5. Deglaze with Guinness - Add Guinness and let it simmer rapidly, scraping the base of the pan to loosen any golden bits into the liquid (“fond” = free flavour!), until the Guinness is reduced down by 75%.
6. Sauce - Lower heat to medium and add remaining butter. Once melted, sprinkle flour all across the surface and stir for 1 minute - it will look pasty. While stirring, pour in half the stock. Keep stirring until the flour paste dissolves into the stock, for lump-free sauce (yay!). Then add remaining stock, water, tomato paste, 1/4 tsp salt and 1/2 tsp pepper, stir well.
7. Simmer - Add the mushrooms plus all mushroom juices accumulated in the bowl into the pan. Simmer for 10 minutes or until the liquid reduces down into a fairly thick gravy and the mushrooms become soft. (Meanwhile, start the mash)
8. Thicken sauce - Add the chicken (plus all juices) and simmer for another 2 to 3 minutes until the gravy is quite thick and you can draw a path on the base of the pan. (Sauce thickness now = sauce thickness once baked). Taste - add more salt if needed (I don’t).
9. Assemble - Pour into a 1.5 - 2 L (6 - 8 cup) baking pan and smooth the surface. (Note 5 for other pan sizes)
10. Preheat oven to 200°C / 390°F (180°C fan-forced).
11. Duchess potato topping - Pipe mounds of mashed potato swirls on the surface. My swirls have a 4.5cm base (1.6"), about 4cm tall (1.4"), then I fill gaps with small swirls/blobs. I use all the mash! Drizzle with melted butter, sprinkle with parmesan. (Note 6 for no piping bag)
12. Bake for 30 minutes, rotating the pan at the 20 minute mark.
13. Serve - Rest for 10 minutes, sprinkle with parsley if using. Attack!
14. Make mash - Put the potatoes into a large pot of cold tap water. Bring to a boil over high heat then cook for 15 minutes until soft. Drain, pass through a potato ricer (smoother) or mash well with a potato masher in the now empty pot. Add butter, milk, 1/2 tsp salt and 1/8 tsp white pepper, stir through - it should be creamy but not loose (so it holds its form when piped).
15. Piping bag - Transfer mash into a piping bag fitted with a star tip. (Note 6 for no piping bag)