Homemade Chicken Pot Pie - Pankobunny

Ingredients

• 6 tbsp butter
• ¾ onion (finely chopped)
• 1 stalk celery (diced)
• salt & pepper
• 6 tbsp flour
• 3 cups chicken stock
• 1 cup milk
• 1 large potato (diced and blanched)
• 1 large carrot (diced and blanched)
• 1 cup frozen peas (defrosted)
• 1 cup frozen corn (defrosted)
• 5 button mushrooms (halved and sliced)
• 2 chicken breasts (cooked and roughly chopped)
• basic pie crust (rolled to 1/8-inch thick)
• 1 beaten egg