1. To make the crust: Combine flour and salt in a food processor. Scatter butter over flour mixture and pulse into pea-sized pieces, 6 to 8 times. Transfer to a large bowl. Sprinkle water over flour mixture and stir until no dry flour remains. Divide dough and form each half into a 4"-wide disk; wrap in plastic and refrigerate for 1 hour.
2. To make the filling: Heat oven to 400 degrees. Coat chicken with 1 1/2 teaspoons oil, season with salt and pepper, and place on a baking sheet. Toss squash and mushrooms with remaining 1 tablespoon oil, season with salt and pepper, and scatter around chicken. Roast until chicken is cooked through and squash is tender, 25 to 30 minutes.
3. In a large saucepan, whisk together 2 1/2 cups cream and chicken base and bring to a simmer over medium-high heat. Reduce heat to medium, add thyme, and simmer until reduced by half, about 15 minutes. Shred chicken and gently fold into reduced cream mixture along with roasted vegetables. Season with salt and pepper to taste.
4. To assemble: Whisk together egg and remaining 1 tablespoon cream; set aside. On a lightly floured counter, roll 1 disk of dough into a 12" circle. Carefully transfer to a 9" pie dish and trim overhang to 1/2" beyond rim of dish. Fill with chicken mixture. Roll remaining dough into a 12" circle and carefully place it on top of filling; trim overhang to fit with bottom crust. Pinch edges of dough together, then fold under so dough is flush with the edge of the dish. Use your fingers or a fork to crimp edges, cut four 2" slits on surface, and brush all over with egg mixture. Transfer to a rimmed baking sheet and bake until crust is golden brown, 40 to 45 minutes. Let rest 20 minutes before serving.
Source: Hannaford fresh Magazine, January - February 2017