Chicken & Mushroom pan pie

Heat a large oven-proof casserole on the hob and add the oil. Add the sliced onions, mushrooms and garlic. Cook out for 4-5 minutes, then add the butter. When the butter has melted, add the flour and stir well with a wooden spoon, cooking out the flour for 3 minutes.

Next, add the chicken stock and bring to a simmer, stirring well and regularly so there are no lumps of flour. Allow to simmer until the sauce thickens, around 3 minutes, then stir through the cream and remove from the heat. Stir in the Dijon mustard and grated parmesan. Add the cavolo nero, tarragon and leftover chicken and stir it through, then check the seasoning and allow the mix to cool in the pan.

Pre-heat the oven to 200c. When the mix has cooled, roll out the puff pastry sheet and place on top of the pan, pressing it down gently onto the chicken mix to remove any air. Pinch the pastry all along the edge of the pan, then carefully cut off any excess pastry overhanging.

Brush the pastry evenly with egg wash and sprinkle the sesame seeds on top. Place the pan in the oven and cook at 200c for 30 minutes until browned. Remove from the oven and allow to rest for 10 minutes before serving.