Chicken Potpie

INGREDIENTS

• 2 1/4 cups all-purpose flour
• 3/4 tsp. salt
• 12 Tbs. (1 1/2 sticks) cold unsalted butter,
• cut into 1/2-inch cubes
• 1/2 cup ice water, plus more as needed
• 14 Tbs. (1 3/4 sticks) unsalted butter, cut
• into 1/2-inch cubes
• 1 cup plus 2 Tbs. all-purpose flour
• 1/3 cup dry sherry
• 2 Tbs. chicken demi-glace
• 6 cups chicken stock
• 1 1/2 tsp. chopped fresh thyme
• 1 bay leaf
• 1 large yellow onion, chopped
• 3 celery stalks, sliced
• 2 carrots, peeled and cut into slices
• 1/8 inch thick
• 3 oz. white button mushrooms, cut into
• 1/4-inch dice
• 6 oz. small red-skinned potatoes, cut into
• 1/2-inch dice
• 3 cups cubed cooked chicken
• 1 cup fresh or frozen peas
• Salt and freshly ground pepper, to taste
• 1 egg, beaten with 1 tsp. water