For serving: a peppery green salad with arugula and baby spinach
Preheat the oven to 375 degrees F. Butter a 9-by-13-inch baking dish.
To make the filling, melt the butter in a large pot over medium-high heat, then add the onion, carrot, celery and parsnips. Season with salt and pepper and stir them around until the onions start to turn translucent, about 3 minutes. Add the wine and cook for another minute. Sprinkle over the flour and stir it in to incorporate. Cook for a minute or two, but do not let it brown. Add the broth and stir, working out any lumps. Lower the heat to medium and cook until it starts to thicken, 2 to 3 minutes. Stir in the green beans, thyme and turmeric. Fold in the Shredded Boiled Chicken and cook until heated through. Add the half-and-half, taste and adjust the seasoning. Add more broth if it is too thick. Pour the hot filling into the prepared baking dish.
Brush the edges of the dish with the egg wash. Lay the pastry over the top, press down the edges and brush the top of the pastry with the egg wash. Cook until the crust is golden brown, about 45 minutes.
You can also assemble the pie ahead of time. If you are making it ahead, allow the filling to cool, cover and place in the fridge. When you want to cook the pie, brush the edges of the dish with the egg wash, add the filling to the dish, lay the pastry over the top and press down the edges. Brush the pastry with the egg wash and cook at 375 degrees F until the crust is golden brown, about 1 hour.
Serve the chicken pie with a peppery salad of arugula and baby spinach.
Pour the broth into a large pot and bring to a boil. Add the chicken pieces and bring back to a boil. Turn the heat to medium low and simmer until the chicken is tender, about 45 minutes.
Remove the chicken from the pot and set it aside to cool briefly. Remove the skin and bones and shred the chicken.