Instructions:

1. Preheat the Oven: Preheat your oven to 375°F (190°C).
2. Prepare the Crust: Roll out the pie crust and press it into a tart pan or a pie dish. Trim any excess crust hanging over the edges.
3. Mix the Filling: In a large mixing bowl, combine shredded chicken, chopped spinach, diced potatoes, cheddar cheese, Parmesan cheese, mayonnaise, Greek yogurt, minced garlic, dried thyme, salt, and black pepper. Mix well to ensure even distribution of flavors.
4. Fill the Tart Shell: Spoon the chicken and vegetable mixture into the prepared pie crust, spreading it evenly.
5. Drizzle with Olive Oil: Drizzle a bit of olive oil over the top for a golden finish.
6. Bake: Place the tart in the preheated oven and bake for 25-30 minutes or until the crust is golden and the filling is heated through.
7. Serve and Enjoy: Allow the tart to cool for a few minutes before slicing. Serve warm and savor the delicious combination of roasted chicken, potatoes, and spinach in every bite.

Note: Feel free to customize the tart by adding your favorite herbs, or experimenting with different cheeses for a unique twist