The Waverly Inn Chicken Pot Pie

Preheat oven to 425 degrees F. Prepare chicken and stock: Place chicken, onion, celery, carrots, salt, and pepper in large stockpot; cover with water. Simmer in covered pot until chicken is no longer pink, approximately 25 minutes. Strain the broth, and set aside to use in the chicken cream sauce. Remove chicken and cool; cut into bite-size pieces. Prepare chicken sauce: Melt the butter in a medium saucepan. Once the butter has melted, stir in the flour. Add the reserved chicken stock and heavy cream. Stir constantly until mixture comes to a boil. Reduce heat and simmer for 2 minutes. Remove from heat, add Tabasco, Worcestershire, salt, and pepper. In a nonreactive bowl combine baby carrots, peas, mushrooms, pearl onions, and chicken. Pour mixture into a 9" by 13" casserole dish. Pour the chicken sauce over the mixture. Cut puff pastry to fit casserole dish, leaving a 2-inch border. Lay puff pastry over filling crimping edges, trimming edges if necessary. Cut a hole in the center of the pastry to allow steam to escape. Brush egg over crust. Bake until crust is golden brown, and filling is bubbly, approximately 25 minutes. Let stand 5 minutes before serving.