Preheat your oven to 350°F (175°C).
In a large mixing bowl, combine your leftover protein (e.g., chicken) and vegetables.
In a separate bowl, mix together your creamy sauce ingredients with salt and pepper to taste.
Pour the creamy sauce over the chicken and vegetables, mixing until well coated.
Transfer the mixture into a greased casserole dish.
Sprinkle shredded cheese over the top, and if you’d like, add breadcrumbs for an extra crunchy layer.
Bake in the preheated oven for about 25-30 minutes or until golden and bubbly.
Let it cool for a few minutes before serving. Enjoy your delicious creation!