Chicken pot pie

Instructions

• Line two 9 x 13-in. baking dishes with heavy-duty foil, leaving 5 in. of overhang on all sides.

• Melt butter in a large pot over medium heat. Add onion and cook until softened, about 5 min. Stir in flour and cook for 1 min. Gradually pour in chicken broth and milk while whisking, then bring to a simmer. Add chicken, potatoes, salt and pepper. Bring to a boil, then reduce heat and simmer over medium-low heat, stirring occasionally, until chicken is no longer pink and potatoes are tender, about 15 min.

• Remove from heat, then stir in frozen peas and carrots. Divide mixture between prepared baking dishes.

• To freeze: Let filling cool completely to room temperature, about 45 min. Wrap filling tightly with overhanging foil. Freeze until firm, at least 2 hours. Remove foil packet from baking dish, then wrap well with plastic wrap. Label and date, then return packet to freezer for up to 3 months.

• To bake from frozen: Position rack in bottom third of oven and preheat to 400F. Remove plastic wrap and return foil packet to baking dish. Bake for 30 min. Roll out puff pastry on a lightly floured surface to the size of the baking dish. Unwrap foil and cut away overhang with scissors. Stir filling, then spread evenly. Place pastry on top, then cut slits with a paring knife and brush pastry with milk. Continue baking until pastry is golden brown and filling is hot in the centre (it should reach 165F with an instant-read thermometer), about 20 min. Let stand for 10 min before serving.