Season the chicken with salt and pepper. Heat the olive oil in a large pan or casserole over medium-high heat. Working in batches, sear the chicken for 7–8 minutes on each side until deeply caramelised. Set aside.
Reduce the heat to medium. Add the carrot, onion, celery and garlic to the same pan and cook for 6–7 minutes until softened. Add the Gewürzhaus Bavarian Roast Chicken Spice and cook for 1 minute, then add the butter and flour and cook for 2–3 minutes, stirring well.
Add the white wine and deglaze the pan, stirring for 2 minutes. Add the stock and cream and stir to combine. Return the chicken and resting juices to the pan along with the bay leaves, tarragon and mustard. Mix well, reduce the heat to low-medium and simmer for 30–35 minutes, stirring occasionally and scraping the bottom, until the chicken is tender and the sauce has thickened.
Remove the chicken and allow to cool for at least 30 minutes. While the chicken is cooling, preheat the oven to 200°C fan-forced and transfer the pastry to the fridge to thaw slowly. Once cool enough to handle, pull the meat from the bones and discard the bones and bay leaves.
Stir the peas through the filling and transfer to 6-8 individual pie dishes or one oven dish. Cut the pastry to fit the dish, leaving a 2 cm overlap. Brush the rim of the dish with beaten egg, lay the pastry over the top and fold down the edges. Brush the surface with a beaten egg and cut a 2cm slit in the centre to allow steam to escape.
Bake for 25–30 minutes until the pastry is golden. Serve immediately with roasted vegetables or mashed potatoes.
