Casserole Queen Pot Pie

Name: Casserole Queen Pot Pie
Ingredients: 1 sheet frozen puff pastry; 2 tablespoons butter; 1 roasted chicken, shredded; 1/4 cup chopped red sweet pepper; 2 medium shallots, thinly sliced; 2 tablespoons all-purpose flour; 3/4 teaspoon salt; 1/2 teaspoon dried tarragon, crushed; 1/4 teaspoon black pepper; 2 cups milk; 1 cup heavy cream; 1/3 cup dry white wine; 1 1/2 cups peas, blanched; 1 1/2 cups carrots, blanched; 2 potatoes, peeled, diced, and boiled; 1 egg plus 1 tablespoon milk, for egg wash