Pastry:

1 1/2 c. all-purpose flour
1 tsp. salt
1/3 c. butter, cut into pieces and chilled
1 large egg
2 to 3 tbsp. ice water

Filling:

3/4 c. dry white wine or water
1 1/2 c. whipping cream
2 tbsp. all-purpose flour
1 1/2 tsp. paprika
1/2 tsp. salt
1/2 tsp. black pepper
3/4 c. chicken broth
1 large egg, slightly beaten

To prepare pastry, in a medium bowl, mix together flour and salt. Using a pastry blender or 2 knives, cut butter into flour until coarse crumbs form. In a small bowl, beat together egg and water. Add to the flour mixture. Mix together until a soft dough forms. Shape into a disk; wrap in plastic wrap and chill for 1 hour.

To prepare the filling, place chicken in a 2-quart casserole. In a large skillet, melt butter over low heat. Add mushrooms. Increase the heat to medium-high and sauté until browned and the liquid evaporates, about 5 minutes. Add the wine. Cook until almost evaporated, about 2 minutes. Add mushroom mixture to chicken; stir to combine. In a medium saucepan, whisk together cream, flour, paprika, salt and pepper over low heat. Cook until thickened, about 5 minutes. Whisk in broth. Pour sauce over chicken mixture. Preheat oven to 400°F.

On a lightly floured surface, using a lightly floured rolling pin, roll the pastry to fit the top of the casserole. Place on top of pie; trim and seal the edges. Roll out trimmings and cut into shapes, if desired. Brush pastry with beaten egg and top with decorative pastry pieces, if desired. (If so, brush with egg again.)

Bake until the filling is bubbly and crust is browned, about 25 to 30 minutes. Transfer to a wire rack to cool slightly. Serve warm.