Preheat your oven to 375°F. This will ensure that your pie bakes evenly and the cheese melts perfectly.
In a large skillet, melt butter over medium heat. Add the chopped onion, bell pepper, carrot, and celery. Cook until the veggies soften and the onion is tender and translucent, about 5 minutes. Make sure to stir occasionally to prevent burning.
Sprinkle in the basil, thyme, salt, pepper, and garlic. Stir well and cook for another 30 seconds until the garlic is fragrant. Then, sprinkle flour over the veggies and stir to combine, cooking for 1 to 2 minutes to eliminate the raw flour taste.
Pour in the chicken broth and add the chicken bouillon cube, stirring to dissolve the cube fully. Let it cook for about 5 more minutes until the sauce thickens, stirring occasionally to avoid sticking.
Fold in the turkey and peas. Stir everything together and bring the filling back to a light boil. This step ensures that the turkey heats through and all flavors meld together nicely.
Spread the mashed potatoes over the filling, smoothing it out with a spoon. Use a fork to rough up the top slightly, which helps create a nice texture. Take this opportunity to sprinkle mozzarella cheese evenly over the top.
Transfer the skillet to the preheated oven and bake for 30 minutes or until the cheese is melted, golden brown, and bubbly. This is when your kitchen will start smelling amazing!
Once baked, remove from the oven and let it cool slightly. If desired, garnish with parsley before serving warm. Enjoy every bite of this comforting pie!
