Get Ready to Bake: Preheat your oven to 400°F (200°C). Lightly spray an 8x8 inch baking dish with cooking spray to prevent sticking.
Whip Up the Creamy Base: In a large mixing bowl, combine the softened cream cheese, sour cream, mayonnaise, and chicken broth. Whisk until it's smooth and well blended.
Season the Flavor: Stir in the dried minced onion, dried minced garlic, Herbes de Provence, salt, and pepper into the creamy mixture. Mix well.
Fold in the Goodness: Gently fold in the cooked turkey and the pre-cooked, shredded spaghetti squash. Make sure everything is nicely coated.
Add Some Cheese: Stir half of the shredded cheddar cheese directly into the turkey and squash mixture. This ensures cheesy goodness in every bite!
Prepare for Baking: Transfer the entire mixture evenly into your greased baking dish, spreading it out smoothly.
Top it Off: Sprinkle the remaining shredded cheddar cheese generously over the top of the casserole.
Bake to Perfection: Place the dish in the preheated oven and bake for about 30 minutes. You'll know it's ready when it's hot, bubbly, and the cheese on top is melted and lightly golden.
Serve and Enjoy: Let the casserole cool for a few minutes before serving. This hearty, healthy, and easy meal is perfect for using up leftover turkey!