Chicken Pot Pie with Chunky Vegetables

Ingredients

• 2 tablespoons olive oil
• 3 leeks, rinsed, white and pale green parts coarsely chopped
• 2 celery stalks, coarsely chopped
• 2 large carrots, peeled and thickly sliced
• 1 large red potato, unpeeled and cut into bite-size chunks
• 1 cup thickly sliced mushrooms
• 3 tablespoons all-purpose flour
• 1/2 teaspoon dried thyme, crumbled
• 1/4 teaspoon salt
• 1 can (14 1/2 ounces) reduced-sodium, fat-free chicken broth
• 2 cups bite-size pieces cooked chicken
• 1 cup fresh or frozen green peas
• Pre-packaged pastry for single-crust 9-inch pie
• 1 large egg whisked with 1 tablespoon milk for glaze