Preheat the oven to 400°F (200°C).
In a bowl or food processor, mix the flour, sugar, and salt. Add the cold butter and work it in until the mixture looks like coarse crumbs.
3 cups all-purpose flour, 1 teaspoon cane sugar, ½ teaspoon salt, 1 cup cold unsalted butter
Add the ice water a little at a time, mixing just until the dough comes together. Divide into two discs, wrap, and chill for 30 minutes.
8-10 tablespoons ice-cold water
Roll out one disc and fit it into a greased pie pan. Bake for 10 minutes, then remove from the oven and reduce the temperature to 350°F (175°C).
Melt the butter in a large skillet over medium heat. Add the onion and cook until soft, about 5 minutes. Stir in the garlic and cook for another minute.
2 tablespoons unsalted butter, 1 cup yellow onion, 1 teaspoon garlic
Add the chicken, sun-dried tomatoes, oregano, paprika, salt, and pepper. Mix well.
2 cups cooked chicken, ½ cup sun-dried tomatoes, 2 teaspoons dried oregano, ½ teaspoon paprika, Salt and pepper
Sprinkle in the flour and cook for 1–2 minutes. Slowly pour in the chicken broth, stirring to combine.
2 tablespoons all-purpose flour, 1 cup chicken broth
Add the heavy cream, spinach, mozzarella, and half of the Parmesan. Cook for a few minutes, until the spinach wilts and the filling becomes thick and creamy. Remove from heat.
1 cup shredded mozzarella, 1 cup heavy cream, 1 cup fresh baby spinach, ¾ cup grated Parmesan
Pour the filling into the pre-baked crust.
Roll out the second disc of dough and place it over the top. Seal the edges, trim any excess, and cut small slits to let steam escape. Brush with beaten egg if desired.
Bake at 350°F (175°C) for 30–40 minutes, until the crust is golden brown.
Let the pie rest for 10–15 minutes before slicing. Serve warm.