Chicken Potpie

To serve for three, use 1 1/2 tablespoons of flour, cut the phyllo into quarters, and halve the remaining ingredients. Bake the casseroles in three 10-ounce tins. (Place a quarter of a phyllo leaf on each pan; discard the remaining quarter.) Bake for 15 minutes or until the tops are golden. To reduce the cooking time, look for sliced vegetables in the supermarket.
Preheat the oven to 375 degrees.Melt the butter in a large roasting pan over medium-high heat; add the butter. Add the potatoes and the following 6 ingredients (with thyme added) and simmer for 5 minutes. Reduce the heat to medium-low ; sprinkle the vegetables with flour. Cook for 5 minutes, stirring frequently. Add the milk and broth. Increase heat to medium-high; bring to a boil. Reduce the heat and simmer for 5 minutes or until thickened. Add the chicken, green peas, salt and pepper.Spoon the mixture into a 3-liter baking dish. Place 1 phyllo leaf on a large cutting board or work surface (cover with the remaining batter to keep it dry); drizzle lightly with cooking spray. Repeat applying layers with cooking spray and remaining phyllo. Layer the fillets on top of the mixture on a platter. Place the dish on a baking sheet. Bake at 375 ° C for 30 minutes or until the top is golden brown.